# Solved: Central heating problems with radiators



## H_H

In a nutshell.... I've tried everything, but can't work out what's wrong!

- Feed water tank - full
- All radiator bleed valves closed
- All radiator control valves open
Problem - Central heating off or on - No warm radiators.
- When bleeding radiators downstairs - get water out
- When bleeding radiators upstairs - no water out and no air pressure either
- Hot water ok.
- Pump has been vented and is working, can see it going round, but neither inlet or outlet pipes to pump are warm.
System is a gas back boiler, with hot water tank above.

Anyone got any sugestions?

Thank you!


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## blues_harp28

What part of the world are you?
Are all cold and hot taps - downstairs and upstairs working - with full running water?
Is there an air bleed key on the boiler?
It sounds like an air block.


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## telecom69

Depending on how old the system is,and how it has been maintained, sometimes the pipes etc get sludged up and it can be really bad and stop water flow ...if this was my problem ,I would be connecting a hosepipe to the drain valve of the lowest radiator on the system and giving it a flush out ....Im not saying that this is your problem but its worth consideration if the system is a bit old,or indeed has microbore piping ....


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## blues_harp28

telecom69 said:


> Depending on how old the system is,and how it has been maintained, sometimes the pipes etc get sludged up and it can be really bad and stop water flow ...if this was my problem ,I would be connecting a hosepipe to the drain valve of the lowest radiator on the system and giving it a flush out ....Im not saying that this is your problem but its worth consideration if the system is a bit old,or indeed has microbore piping ....


Good point.
Let it run for as long as you can [outside of the building] - and you should hear the entire system refilling with water if all is Ok.


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## H_H

blues_harp28 said:


> What part of the world are you?
> Are all cold and hot taps - downstairs and upstairs working - with full running water?
> Is there an air bleed key on the boiler?
> It sounds like an air block.


Yes, there is hot and cold water in all taps, where would the bleed for the boiler be? I've got a gas fire in the living room downstairs which is in front of the boiler and I'm thinking I may have to take that off and find a bleed behind it... but shouldn't all bleed valves be above the thing you're trying to bleed and not below? It doesn't make sense...


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## H_H

blues_harp28 said:


> Good point.
> Let it run for as long as you can [outside of the building] - and you should hear the entire system refilling with water if all is Ok.


If the system was refilling it'self at all then I would have heard that happening after bleeding the downstairs radiators wouldn't I? I'm thinking the air in boiler is the first thing to try...

Thanks for all the advice, I'll come back if I can't find the valve orit doesn't work!


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## blues_harp28

Most boilers - not sure about a back boiler - have an upstanding pipe that has an air bleed key.
It need not be up high - as it for air, not water.

I'd connect a hosepipe to the drain valve of the lowest radiator on the system - and the other end to the cold tap in the kitchen.
Most main water pipes into the house, start with the cold tap and that has the full mains pressure.
Connect lowest radiator - to the cold tap and run water from that radiator throughout the entire system..

Check that all radiator in and out valves are open.
You will need to use some sort of pipe clips to make sure that the hose stays on.

In one of the radiators - upstairs - remove the bleed screw, that will help bleed the system of air.


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## blues_harp28

If you have hot water throughout the house - then the boiler must be Ok, as well as the water pump.
Forget trying to bleed the boiler of air and refill the entire heating system, with water from the downstairs radiator.

That will remove all air from the system.


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## H_H

The story continued, I found that there may be air getting in through one of the other radiator valves and the bleed valve for another one was rounded off, so I took the opportunity to replace them and then tried your idea (after purchasing the essential jubilee clip for the hose!). 

I was a bit worried about overfilling the feed and expansion tank in the loft, so only turned the hose on quickly and ran around all the upstairs radiators bleeding them off, was very pleased to hear them all hiss away and then dribble. Turned on the central heating, pump kicked in, pipes warmed up and we're away!

Thank you very much to telecom69 :up: and blues_harp28 :up: your advice was a brilliant! Thought I'd have to get a plumber in. Have learnt a lot about my central heating system doing this.  

Thank you!


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## blues_harp28

Good news to hear - my 35 years in the building trade, has not gone to waste.

:up: 

You can mark it Solved - at thread tools at the top of the page.


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## H_H

It's happened again! My central heating and water heating have all stopped working (I've done no work this time) and when I checked the radiators I've got no water in any of the upstairs ones and no water at the pump air valves either! So this time i know what I have to do and can get the garden hose out again, but why would this keep happening? 

If - I have an open/not sealed bleed valve - then surely I'd notice water pouring out somewhere and the feed/expansion tank should be doing it's job and keeping the system topped up anyway??
If - i have a leak somewhere else in the house - then I'd notice water pouring out somewhere and the feed/expansion tank should be doing it's job and keeping the system topped up anyway?

Therefore - could it be that my feed and expansion tank isn't doing what it's meant to be doing? i.e. as the system heats up each time and a little water trickles over into the tank, then it isn't re-filling when the system goes cold again? But, this should mean that i'd hae noticed the overflow to my feed/expansion tank dripping (out side the house) but it isn't....

So still very confused!!!!!

Any advice/suggestions welcome!


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## blues_harp28

Hi the expansion tank - is just for the central heating, as water heats up it expands and so the tank is for safety, that is all.
And it will take forever to fill up to the overflow pipe and discharge outside of the house.

You have not said - if you are getting hot and cold water to all taps.

Check the main water tank - does the ball valve operate Ok - is the tank full of water and if you move the ball valve down - does water enter the tank?
How much water is in the tank - should be 6-8 inches from the top.

If little or no water in the main tank - put a hose on the kitchen cold tap and the other end on the kitchen hot tap. 
Cut a piece of hose to fit between the two.
Open the hot tap fully and then the cold which should have mains pressure and run water from the cold tap, through the hot tap and refill the system

Again you will need to use clips to hold the hose on both taps.

The water from the downstairs supply - may not be reaching the main water tank upstairs - air block again, maybe.


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## H_H

I'm assuming that the water tank is ok, as there is water coming out of all of the hot taps, it's just cold! I'm wondering whether there's a problem with the three-way valve?


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## blues_harp28

The main water tank will feed the small tank above the boiler - if you are getting cold water out of the hot tap..
Is the boiler starting up and is the pump working.

What is this 3 way valve?


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## H_H

The boiler is starting and the pump is going round (you can see something rotating when the plug is out) but someone's told me that unless it's in water, they can drop down inside or something. The valve is something that can be on "auto" or "Manual" I'm not really sure what it does.


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## H_H

I think it's one of these: http://www.deals4homes.co.uk/images/centheat2.gif


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## blues_harp28

For some reason your link is not connecting.

If the pump has no water present - it will burn out and even though you can hear it working, does not always mean that water is being moved by it.
If water is present in hot and cold taps - all be it cold, from the hot tap and the boiler is firing up, my guess would be the pump is not working.


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## blues_harp28

The "auto" or "Manual" would mean that you can set it to run by a timer or manually turn on the hot water.
Is there a timer and have you tried both manual and auto?

'you can see something rotating when the plug is out'
Pump working with the plug out?

Is it a Grundfos water pump?
http://www.google.co.uk/search?rls=...ogle+Search&meta=&aq=f&aqi=&aql=&oq=&gs_rfai=


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## H_H

Yes, it is a grundois pump, 15/50 and the three way valve is a honeywell. I've tried it on auto and manual and yes there is a timer system which was working fine up till now!
Yes, you can see something rotating when you take the front screw plug out. I thought is was the pump, but am coming to the conclusion that maybe it's the motor that I can see rotating!


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## blues_harp28

Can you feel warm - hot water on the inlet side of the pump but still cold on the outlet side?
Is there a screw to increase the speed of the pump - usually on the front of the pump?


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## H_H

Nope, all pipes are cold (and empty!) there is no water in any of the bleed-air valves near the pump either. There is a knob on the side - with 3 pump speed settings. The front of the pump has the bleed/plug (as above)... I think that when I flooded up the system last week I may have dislodged debris into either the pump or valve, but if the valve was not working then I would at least be getting hot water?


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## blues_harp28

Any debris [sludge] will collect in the lowest point in the system - or the last radiator - or in the water pump.
Can you check if the hot water tank [above boiler] has water present - that will eliminate the water flow from the main water tank, to the hot water tank.

Any strange noise from the boiler - as if no water is present?


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## H_H

The pump is making such a racket it's hard to hear whether there's funny noises in the tank or boiler. How would I check the tank has water? If I've got water coming out of the hot taps doesn't that mean I've got water in the hot water tank?


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## blues_harp28

If the pump is making 'such a racket' usually means at some time, it was running dry [no water present]
My question about the hot water tank and boiler - is there enough water from the tank reaching the boiler or is it by-passing the boiler to the hot taps.

But all point to a Faulty Pump - approx cost £80.
Labour cost in the UK - approx £180 - £240 
Unless you DIY - not too difficult with the right tools etc.


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## Lockeyp

Stupid Q. But has the Gas fire (back boiler) fitted with a switch or a lever that allows you to switch from hot water to Hot Water/Central heating, if so ensure that the switch is on to the latter.,


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## H_H

Nope, i don't think there's a switch! I'm gonna have to buy a new pump I think... or call a plumber! oh no!


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## Lockeyp

Another stupid Q did you get a manual with the pump because they usually have a fault finding section somewhere in it..

Sorry, can't think of anything else at the moment... But GOOD LUCK

Keep us posted as to the outcome and the remedy when you find it .

Thanks

Lockeyp


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## blues_harp28

Worth having a plumber check it out - but ask for an estimate first.
And they should give you a free estimate and know what the problem is and the cost to repair it.

If you need info on how to change said pump - let me know.


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## H_H

Nope, sorry no manual with the pump, no manuals with any of the house when I brought it 
I'll get a plumber in tmrw or wednesday.
Thank you!


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## H_H

Update:

The story with the plumber... He took off the motorised valve and confirmed that it was working correctly. He put a long wire down the cold feed and confirmed that it was clear to the first elbow. We opened an upstairs radiator valve and he blew with a pipe down the cold feed to see if any water would come out of the upstairs radiators - nothing. So he thinks a blockage in some of the cold water feed pipe (there's only two bends) so, we've filled the system back up again from the garden hose, nice warmth (pump definatley working) - we'll see how long it lasts and at the weekend I'm going to drain the whole system down (with the ball ***** on the tanks upstairs tied up) and check that the feed/expansion tank doesn't empty. If it doesn't empty then we'll confirm that that pipework is blocked and he's going to cut it all out on tuesday and replace with new for £60 (plus £25 for todays consultation).

If the feed tank does drain... then we're back to the drawing board!


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## blues_harp28

Thanks for the update - did you try, connecting a short piece of hose to the cold and hot tap in the kitchen?
That will refill the system using mains pressure from the cold tap.

Fitting a hose from the kitchen tap to the nearest radiator, may only free the hot water pipes to the radiators and not the main water feed to the main tank.

If you drain the whole water system down - then when you refill, there is more of a chance of an air block.
Anyway the plumber seems to be on the case and not charging too much.


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## H_H

Nope, I didn't try the hot to cold tap, sorry as I have a mixer tap in the kitchen, so wasn't sure how this could work. I understand about the air blocks, but havae played with the system so much over the last few weeks that at least I understand how to get rid of the air! The plumber has also told me to buy some de-sludge stuff and so when he's done the pipe replacement I'll give the system a sludge remover thing, then drain again in 28 days and then refill with an inhibitor etc. It sounds like a good idea to give the system a clean out!


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## wacor

blues_harp28 said:


> Worth having a plumber check it out - but ask for an estimate first.
> And they should give you a free estimate and know what the problem is and the cost to repair it.
> 
> If you need info on how to change said pump - let me know.


No offense but you get what you pay for.

I am in a service related business and it drives me nuts that people expect me to spend money to come out to find out what is their problem. It costs money for labor, truck, etc.

It is fine to expect a rebate on determining the problem if the repairs are done but no way am I gonna go out to troubleshoot a problem for free. If there is major work I can rebate the service call but even then I will and anybody else in business would figure that into the final cost.

If somebody knew what was wrong they could expect a free estimate over the phone. If the customer has not clue what is wrong then I am not going to go to the expense of determining what is wrong and let somebody else get the work.

If you want a free estimate you risk getting a lousy determination of what is wrong. Sounds like a pump over the phone and you want a free estimate then guess what you have a good chance of getting the pump replaced whether it needed it or not.

Just one persons opinion.


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## blues_harp28

It is true that that you get what you pay for.
But I have been in the building trade here in the UK for over 35 years and have always given a written free estimate.
And with most of the work coming from recommendations and with little need to advertise - it seems to work.

Most new customers may get at least 3 estimates and will choose, sometimes because of the cost or from the fact that you have been recommended.
And it would be very difficult to say yes I will fix it for you, without saying what the problem may be.

Most builders if not all in the UK - give free estimates.
Again - just one persons opinion.


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## wacor

blues_harp28 said:


> It is true that that you get what you pay for.
> But I have been in the building trade here in the UK for over 35 years and have always given a written free estimate.
> And with most of the work coming from recommendations and with little need to advertise - it seems to work.
> 
> Most new customers may get at least 3 estimates and will choose, sometimes because of the cost or from the fact that you have been recommended.
> And it would be very difficult to say yes I will fix it for you, without saying what the problem may be.
> 
> Most builders if not all in the UK - give free estimates.
> Again - just one persons opinion.


Fair enough

I guess my perspective is that it is like calling up a doctor and asking for a free estimate. You would not expect them to diagnose your illness for free. That is even when you drive to their office let alone if they were to come to your house.

I would compare it to being ill versus needing a prescription. If you know what prescription you need it makes sense to be able to get a free estimate for what they would cost. But if you have no idea what prescription you need then somebody should pay for the diagnosis.

I do give out lots of free estimates. If somebody knows what they need I will come out and look the site over and provide an estimate. But if they have a service issue on something in the house we would work on that requires a technician it is another matter.


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## H_H

Hiya, just to let you all know that I paid my plumber and he came today. He cut out a section of pipework and we did indeed find that the cold fee was blocked solid! He replaced the section and I've put a sludge remover in. No leaks! yeah.
Thank you all for your help and advice.
H


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## H_H

p.s. I'm not giving up the day job! I'm happy to pay others, but I also like to understand what's going on and why! It's the scientist in me... (The investigation can be the most fun bit... or the most frustrating!)


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## blues_harp28

And finally - :up: thanks for letting us know..you may need some heat tonight, feeling a bit cold here in London.


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## H_H

It's like a sauna here! lol


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## Lockeyp

Thanks for getting back to us with the update . H_H ( KEEP THE HOME FIRES BURNING ........) Good Luck.

Lockeyp


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