Central Heating Problem

[Pablo]

My central heating is powered by an Ideal Classic FF gas boiler. All of my radiators are stone cold. The boiler fires up OK and all the burners seem to be OK. After a minute or two the boiler cuts off. The pump is spinning but gets too hot to touch. I have removed and cleaned all the radiators and I have drained the system. The two tanks in the loft seem to have the correct level of water in them. Could you suggest what the problem might be?

Thanks

Pablo

 

[Billy Bob Bob]

do you have a motorized valve in the system?

 

[Centralheatking]

I would look again at the pump - it can be that the impellor has parted company with the motor hence no circulation -hot pump body no water flow coolin it

centralheatking

 

[Pablo]

There is a white plastic box attached to the pipe adjadcent to the pump which has an electric wire running to it. Is this a motorised valve?

 

[Pablo]

So even if the pump appears to be spinning when I remove the inspection screw, it could actually not be turning anything?

 

[Billy Bob Bob]

There is a white plastic box attached to the pipe adjadcent to the pump which has an electric wire running to it. Is this a motorised valve?

it could be a picture would help,if it is a motorized valve your problem could be there

 

[mattyp]

Sounds like air to me ! Try venting the pump with a large flat headed screwdriver

 

[Pablo]

I tried to upload a photo but it said it was too large (file size) sorry

 

[Pablo]

How do you vent the pump?

 

[Pablo]

Cut the picture down, is this ok?

 

[Billy Bob Bob]

View attachment 2142

Cut the picture down, is this ok?

your fault could lay here the black lever on the bottom latch it open and try the heating on

 

[Spike295]

Yes that is a motorised valve. Has any work been done to the system recently, ie been drained & refilled. If not & all has been fine untill this happened i would also suggest the pump.

 

[Billy Bob Bob]

are you getting hot water ?if you are it could be the motorized valve if your not back to the pump

 

[Pablo]

The radiators haven't been working for a week. I drained and refilled the radiators today to try to clear any possible air lock after removing all the radiators yesterday for cleaning. I am still getting hot water. I have tried to change the position of the black lever but although it moves a little, it doesn't seem to want to move all the way to the other side.

 

[Billy Bob Bob]

sounds like the motorized valve has failed,push the black clip in on the other side of the valve and remove the white head you will see a brass bit sticking up,put this so it is almost in line with the valve ,remove the cylinder stat from the cylinder this should give you central heating when in hot water mode as temporarily fix you need a new valve or synchron motor

 

[mattyp]

Turn the hot water off at the programmer and turn the heating on , does the boiler still fire and the pump run ?

 

[Pablo]

I have pushed in the black clip and the whole white box has come away from the valve. It has 3 settings on the side of the white box, W, M and H. It seems to want to stay on W. Even when I move the black lever so that it changes to in between M and H, it gravitates back to W. Does the W stand for water?

 

[Pablo]

No matt, we have only been able to get the radiators hot by putting both water and heating on for the last couple of weeks

 

[mattyp]

W- water , H - heating , M - mid position [ ch and hw together ] It should fire the boiler with just the heating on , so as Gas Man suggested it sounds like your valve has a fault . I would be checking that you were getting power to the valve from the heating controls first though .

 

[Pablo]

How can I check that I am getting power to the valve?

 

[mattyp]

You would need a multi meter and have the skills to use one ! Im a little confused now ! You say you get heating by putting the heating and hot water on together ?? I thought you were getting no heating ??

 

[Pablo]

For the last few weeks we have been unable to get the boiler to fire up when just selecting the heating at the controller, so we put both water and heating on and this was working for a while, but the radiators have gradually got colder each day and now they are stone cold with both water and heating switched on at the controller

 

[mattyp]

Have you tried just the cental heating with the white valve head removed ?? [ room stat turned up ]

 

[Pablo]

I put the white head on the valve, pulled the black lever to change the valve setting to M and then removed the white head and switched the heating only on at the controller, but nothing happened

 

[mattyp]

Sounds like a the valve then, but i would be checking the correct voltage was coming into it .Sounds like you will need to get a heating engineer to take a look .

 

[Pablo]

Does the valve turn through 90 degrees when changing from water only to heating or is it less than this?

 

[Spike295]

With the motor off the valve, switch your timeclock to heating only & see if the black marker moves to the H position. If it does then your valve is jammed, if not then it is more than likely just the motor if all was well previously. You can just replace the motor on these valves rather than doing a cmplete valve change.

 

[Pablo]

It didn't move to H so it might be the motor, how much do they cost approx?

 

[Spike295]

The last 1 i picked up a couple of months ago was about £30 for the motor, write down the name & any model numbers & the merchant will be able to match it up. Check that the pin is moving freely on the valve as a complete new valve incl. motor is not a great deal more. From what you say it sounds very much like its just the motor tho.

 

[Spike295]

When you checked if it went to H, you did have the room stat turned up calling for heat didn't you?

 

[Pablo]

Yes I had it turned up. The pin as you call it, is that the brass thing sticking out of the valve? I turned it through about 20 degrees, it didn't seem to want to go any further. I then did what the gasman recommended earlier in the thread about removing the white box and the thermostat from the tank and switched the water and heating on. I am now getting heat in all the radiators. Does this confirm that the valve is Ok, should it only move through about 20 degrees? If I now replace the motorized white box do you think that will solve it? I'm sorry for asking so many questions.

 

[Spike295]

Yes your valve seems ok if you were able to turn it ok & yes the pin will only turn approx. 20 degrees. It pretty much all points to the motor playing up & i wouldn't hesitate in renewing it.

 

[Pablo]

Thanks for all your advice, it has been a godsend. I will replace the motorised part of the valve as soon as I can get hold of one.

 

[Billy Bob Bob]

no your valve is not ok pablo,what you have done confirms its failed,if the brass screw turned ok chances are you just need a new,cheap,syncron motor

 

[Pablo]

One last question, because I drained the radiators today do I have to refill with inhibitor and if so how do I do this?