Keeping the heating on for Christmas!

[Mr Pig]

Hi all,

Perfect timing as ever, the heating is kabluey but I think with some advice I can bodge it into working until I can get an engineer out after Christmas. In a nutshell, what I want to do is stop the boiler from heating the water in the hot water tank while the tank is calling for hot water.

Gravity-fed gas hot water and central heating. The hot water side is working fine, the heating is not. When it started playing up I could get the heating to click on by flipping the switches on the controller a few times. Today it won't come on at all.

I thought it must be the controller but I removed and tested it and seems to be working fine. I also tested the stat and it too works ok. No loose wires, end of my understanding.

However, if I switch the motorised valve to manual then water gets sent to the radiators as well as the water tank. Snag being that once the tank is up to temperature the system shuts off again. If I could shut off the heating water circulation to the tank that would stop it getting up to temperature and keep the heating on. I could then regulate the temperature of the house with the stat on the boiler!

Yeah, I know it's a bodge but it's very unlikely I'll be able to get an engineer out until after Christmas. I left a message on the answerphones of three engineers today and none of them have even called me back.

Would this work? If so, how do I shut of the water heating the tank? I've been looking for a diagram explaining what the valves do etc but I can't find one.

Thank you in advance for any help :0)

Colin.

 

[dilalio]

Change the 3 port valve head.
Post a photo of it.
Hopefully your lucky and it is one you can just change the head. You can even use a regin multipin plug on the cable that goes to the wiring centre so you don't have to open that up and tracing wires to terminals... Assuming it's all wired correctly and was functioning correctly beforehand.
You should go testing things out with a meter first, but, in a jam this would be your best bet as they are a common part to fail.

 

[Mr Pig]

I'll post a picture later, thanks. I've got it running for now. Simple! Had one of those 'Doh!' moments almost as soon as I posted the above. I've just set the hot water tank stat to a higher temperature than the boiler stat...

 

[ianmcd]

you dont have a gravity fed HW system, you have an open vent fully pumped Y plan system

 

[dilalio]

you dont have a gravity fed HW system, you have an open vent fully pumped Y plan system

That confused me a bit at first also but then I read between the lines

 

[dilalio]

I'll post a picture later, thanks. I've got it running for now. Simple! Had one of those 'Doh!' moments almost as soon as I posted the above. I've just set the hot water tank stat to a higher temperature than the boiler stat...

Hmmmn. Not ideal. But If it gets you through... Just don't scald yourselves.

 

[Mr Pig]

Yes, the hot water is rather hot! Seems to be working though. The heating is still on and the house is just about warm enough.

 

[dilalio]

If the 3 port valve is a Honeywell, you could still get one from screwfix or toolstation tomorrow (I think )

 

[ianmcd]

Hmmmn. Not ideal. But If it gets you through... Just don't scald yourselves.

How did we ever survive with gravity fed HW on old systems with no cyl thermostat, OH I remember we turned down the boiler thermostat

 

[Mr Pig]

Change the 3 port valve head.

Do you think the valve would cause the symptoms I'm getting? When I try to put the heating on I get nothing, not even a click. Yes, it is a Honeywells unit.

 

[dilalio]

Do you think the valve would cause the symptoms I'm getting? When I try to put the heating on I get nothing, not even a click. Yes, it is a Honeywells unit.

Yes. If motorised valve doesn't travel across and fire boiler it's a likely suspect but really needs testing out with a meter to be certain.
Up to you to give it a try at this time of year.

 

[Mr Pig]

I think I'll just replace that motorised valve anyway. It's over thirty years old so I reckon it's due! There is a Honeywells valve in Screwfix which looks identical. I assume it's best to replace the whole valve rather than just the head? Annoying thing is that I drained and flushed the system just a few months ago. Now I'll need to drain it again.

 

[Mr Pig]

You can buy the head separately for about half the price of the whole valve.

 

[Mr Pig]

The valve is a Honeywells V4073A 1039. A new one on eBay for £55 so I've ordered it.

Thank you all for the great advice. I'll let you know what happens when I fit the new valve.

 

[ianmcd]

You can buy the head separately for about half the price of the whole valve.

If the valve is 30 years old it is doubtfull if it would have the removable head anyway, they were introduced later than that , for other reading this the removable head has a dimple on the top of the cover, no dimple not removable