Hot water seems to be constantly on?

[mcluskyisms]

Hi,

I recently replaced our faulty Sunvic 207 thermostat with a second hand Sunvic 207 XLS and fitted it (the wiring etc was exactly the same). I have noticed that once the heating has been on that it also seems to have heated the water up too even though we havent selected to heat the water.

This morning I had a look in the airing cupboard and the water tank feels warm and I can hear the pump, it seems the water is being constantly heated up, even though we havent ran the heating or water today.

Has anyone got any ideas what it might be, the only thing I can think is maybe wiring although it was the same wiring diagram as the previous thermostat which we didnt have this fault with.

Cheers

 

[doitmyself]

Could be a motorized valve problem. How many do you have?

 

[mcluskyisms]

Could be a motorized valve problem. How many do you have?

I'm not sure, I'm a novice when it comes to Central Heating. Think I may have found the issue, it seems that when the heating is put on for an hour on the thermostat that the water is also getting turned on to be heated to (even though it is not selected).

That would suggest either wiring fault, thermostat fault or operator error? Hah.

Ive been through the settings and downloaded the PDF instructions from Sunvic and everything seems set up right so I'm guessing the wiring may be the issue.

The old one was fitted as

(N) (L) (X) (X) (HW) (CH) (X = blank, no wire)
(N) (L)(Off)(Off)(0n) (On)

So I fitted the new thermostat the same as both wiring diagrams were the same, Im assuming now that it may be something to do with the blank pins which control off?

 

[melmos]

Could there be a clue in the word 'second hand'

 

[mcluskyisms]

Could there be a clue in the word 'second hand'

I thought that too although the seller had a genuine reason to sell (had just had a full new combi boiler put in) and it was in really good condition (only used for under a year) he also had 100% feedback over many years and over 500 sales, so I dont think the thermostat is dodgy.

Personally I think that there may be a wiring issue with it being a new version of the same thermostat.

 

[doitmyself]

I'm not sure, I'm a novice when it comes to Central Heating. Think I may have found the issue, it seems that when the heating is put on for an hour on the thermostat that the water is also getting turned on to be heated to (even though it is not selected).

Much more likely to be a valve problem.

You will normally have either two 2-port valves (left pic) or one 3-port valve (right pic). If it's a very old system you may have one 2-port valve (left pic). They will usually be near the pump or hot water cylinder.

 

[mcluskyisms]

Much more likely to be a valve problem.

You will normally have either two 2-port valves (left pic) or one 3-port valve (right pic). If it's a very old system you may have one 2-port valve (left pic). They will usually be near the pump or hot water cylinder.


View attachment 14909View attachment 14910

I cant seem to see any valves like that in the airing cupboard (where the pump is) it may be worth mentioning that our central heating is oil (not sure if that makes a difference).

 

[doitmyself]

I cant seem to see any valves like that in the airing cupboard (where the pump is) it may be worth mentioning that our central heating is oil (not sure if that makes a difference).

You said that you had changed the thermostat, but the 207/207XLS is a programmer.

How long have you lived in the house?
What is wrong with the 207?
Were you previously able to have hot water on its own in the winter?
Do you have the old 207?

If so, look on the back and you will see some small switches.

Is the top one set to Pumped (left) or Gravity (right)?

 

[mcluskyisms]

You said that you had changed the thermostat, but the 207/207XLS is a programmer.

How long have you lived in the house?
What is wrong with the 207?
Were you previously able to have hot water on its own in the winter?
Do you have the old 207?

If so, look on the back and you will see some small switches.

Is the top one set to Pumped (left) or Gravity (right)?

Yeah sorry, it is the programmer I changed. We've been here around a year now, the old programmer started making lots of clicky noises constantly when in operation (as if it were tripping off all the time) prior to that it worked flawlessly. Ive still got the old 207 and yes the switch on the back is set to P.

Cheers

 

[doitmyself]

I've still got the old 207 and yes the switch on the back is set to P.

Have you checked the new programmer is also set to P?

A fully pumped system required one or two motorized valves to work correctly, so it's a bit of a mystery why you can't find any valves.

How many water pipes are connected to the boiler?

Where is the pump?

Can you post a pic of airing cupboard - a general view, not a close up of each item is best.

 

[mcluskyisms]

Have you checked the new programmer is also set to P?

A fully pumped system required one or two motorized valves to work correctly, so it's a bit of a mystery why you can't find any valves.

How many water pipes are connected to the boiler?

Where is the pump?

Can you post a pic of airing cupboard - a general view, not a close up of each item is best.

Hi, I decided to turn the electric off and check the rear of the the programmer and it was on the wrong setting (G) I changed it back to P and now it is working spot on, thank you so much for your help!

Cheers

 

[doitmyself]

Hi, I decided to turn the electric off and check the rear of the the programmer and it was on the wrong setting (G) I changed it back to P and now it is working spot on, thank you so much for your help!

So where are the motorized valve(s)???

 

[mcluskyisms]

So where are the motorized valve(s)???

I think they're on the pipes leading to the boiler (there are some grey Sunvic boxes on a couple of the pipes)?

 

[doitmyself]

I think they're on the pipes leading to the boiler (there are some grey Sunvic boxes on a couple of the pipes)?

That sound like them, though they are probably on the flow pipes (hot water away from the boiler) not the return pipes (cooler water back to the boiler).