S plan hot water problem.

[Tom8686]

Hi all.

Have an S plan wiring plan for heating and hot water , the hot water will only work when the heating is on and the room stat turned up.

The mid position valve accuator does not move at all when I select hot water at the programmer.

Wiring all seems correct , a plumber recently changed the motor for the Hot water valve to no avail.

Does anybody know what the problem might be?

 

[Iggifer]

You surely mean you have Y-Plan if you have a mid-position valve? S-Plan is 2 or more valves.

Do the rads get hot when the thermostat is up to and firing hot water?

You could well have a stuck valve, did the plumber not check this?

Have you checked your wiring to the Y-Plan diagram? I guess not if you thought it was S-Plan

 

[chivers67]

Yeah sounds like a stuck valve, normally quite easyish to replace and better to do it in summer! Take a photo of it as some are normally a stock item at most plumbers merchants

 

[AndyPRK]

A Y plan doesn't need the motor to move for HW. As HW is the default unpowered state.

So something is preventing the boiler working. Eg the HW stat on cylinder.

 

[chivers67]

what if it's stuck on heating

 

[EFLImpudence]

Heating would be stuck on.

 

[Iggifer]

Then it wouldn't let HW through

 

[EFLImpudence]

a plumber recently changed the motor for the Hot water valve to no avail.

Maybe it is an S plan - and not a mid-position valve.

Get a plumber who knows what he's doing.

 

[ericmark]

I will guess on the micro switch in the motorised valve. I had same problem with daughters system. The wiring diagram is not much help. I was working with this

wiring diagram which shows a single switch inside the valve, on opening however I found multi-switches which to be fair did the same as diagram shows, but using a meter to fault find results were not as expected. I found I could buy the head separate to valve and swapping head cured the problem.

It seemed the problem existed when my daughter bought the house, however some one had latched the motorised valve into the bleeding position so everything seemed to work, actually every time it called for hot water it warmed the radiators, but no one had noticed that, my son-in-law decided to clean the airing cupboard and in doing so knocked the bleeding lever which then returned to where it should have been which then made it so they knew there was a problem.

Clearly not a cure, but it is good to know latching the leaver will make it so it only runs long enough to heat water, the radiators in her house were not on long enough to get hot, they just got warm, hence why not noticed until he knocked the bleeding lever. (Not swearing it was lever for bleeding)

 

[stem]

First you need to be certain what system you have.

Have an S plan

OK you say you have an S Plan

The mid position valve actuator

but a mid position valve is associated with a Y Plan

a plumber recently changed the motor for the Hot water valve

Now we are back to S Plan

So which is it?

Y plan has something like this with 3 pipe connections

Untitled

• stem
• 1 Apr 2010
• 8

S plan has two (or more) of something like this with 2 pipe connections

Untitled

• stem
• 26 Mar 2010
• 6

 

[ericmark]

Both of stems pictures show the lever for bleeding, do check this is not latched on, that was route of problem with daughters heating.