Problems with central heating

[Pagie1980]

Bit of a long story this one not ideal for xmas eve / morning. I have a gas central heating system with a boiler behind the fire downstairs. The hot water tank which was ancient was leaking so my mate who is a plumber replaced the tank. A few days later this started leaking. And some of the water got onto the switch master 3 way valve which then started sticking. So the tank was changed once again as it seemed to be an issue with the tank new tank. Since then things haven't been right I've had to manually switch the 3 way valve and a week or so ago noticed the 2nd new tank was leaking again. So my mates been back and today changed the tank once again. And also this time changed the 3 way valve to a Honeywell model. Well literally just now with both the heating and water switched to off the boiler behind the fire was still on. I found this strange so went to check out the tank and its mad hot. The water has obviously still been heating. The cylinder stat is probably not working at a guess. Or for some reason the boiler is carrying on boiling. I've isolated the boiler now and emptied all the hot water from the tank which was scalding. Once the water was cool again and with the boiler isolated I noticed the central heating pump was still pumping. So I've turned all electrics off now. Now I've heard of wiring differences when switching from switch master to Honeywell. Could it be that something is wired wrong which is causing the boiler to continue. The cylinder stat not to work. And the pump to continue. Greatful for any info at all. It's worrying me as my partners 8 year old son is in the room with the hot water tank. Many thanks in advance.

Stephen.

 

[ShaunCorbs]

tbh as you have said it could be a wiring fault or it could be the stat i know its not the best thing you want to hear but best to get a heating eng out

does the cylinder get warm when you just have the heating on ?

 

[Pagie1980]

Thanks for the reply. To be honest not sure once he'd finished and it seemed to be working I was happy it was up and running again. Obviously at this time of day it's not ideal ! I'm scared to turn any of it back in now. What could happen if the hot water keeps boiling ? He'd also put a new stat in the tank today. Where would I find a heating eng and at what cost ?

 

[Masood]

Most people will charge silly money today, that's if they even come out...

 

[Pagie1980]

Yeah my mate that fitted it is going to come back and check the wiring again. Was wondering if anyone on here would know how to wire it. The original switch master was 5 wires and the new Honeywell is 6. I've found loads of info on how to switch. But he'd already disconnected the old one so its too late to see where that was wired too !

 

[quality]

where are you based?

 

[Pagie1980]

Broadheath altrincham wa145jb

 

[Masood]

The original switch master was 5 wires and the new Honeywell is 6. I've found loads of info on how to switch. But he'd already disconnected the old one so its too late to see where that was wired too !

He's probably better off just rewiring it. Y-plan wiring diagram is free to download from the Honeywell website:

Wiring Diagrams - Honeywell UK Heating Controls

 

[spanner]

Firstly. They're two different types of manufacturers.
If replacing would be easier to get the same as they don't operate the same direction to open / closed,once installed and wired with colours and locations.

 

[Chalked]

Are you sure the valve has been fitted the correct way round?
It should be "a" to radiators and "b" to hot water.