Thermostat Hot Water Cylinder

[NewhouseOldhouse]

Hi

Where would the thermostat be on my hot water cylinder?

Would the immersion heater act as a thermostat?

Thanks

 

[Hugh Jaleak]

Immersion will have its own integral thermostat. If a Cylinder stat is fitted to control a boiler, it should be around 1/3rd of the way up, strapped to the side of the cylinder. Gravity HW systems from an external heat source may not have a thermostat.

 

[NewhouseOldhouse]

mine is a gravity HW system and has no thermostat I take it!!

must a an airlock as the hot water cylinder does not heat hot just warm when oil heating is on for 2 hrs or so!!

 

[Deleted member 267285]

mine is a gravity HW system and has no thermostat I take it!!
must a an airlock as the hot water cylinder does not heat hot just warm when oil heating is on for 2 hrs or so!!

Cylinder will not heat just from central heating, Gravity maybe different. Take and upload a photo of cylinder and any motorised valves. Do you have a programmer?

 

[NewhouseOldhouse]

Yes programmer works twice a day

 

[Deleted member 267285]

Yes there's no thermostat on that cylinder. Depending on which zone valve setup you have, it's probably not sending the water to the cylinder

 

[NewhouseOldhouse]

there is no zone setup the heating is either on or off as in heats rads & water or nothing.

 

[stem]

mine is a gravity HW system and has no thermostat I take it!!

Are you sure that you have a gravity circulation hot water system, in that case your installation is like this. ie Gravity circulation of the hot water and pumped central heating. [Don't confuse gravity circulation with having tank(s) in the loft, that is something else altogether]

Hard to tell in the photo, but the pipes supplying the hot water cylinder look to be 15mm to me.

If that's the case, for gravity circulation 28mm pipes are normally fitted. So, are you sure that it's gravity circulation? and if so has it ever worked?

 

[NewhouseOldhouse]

I have a water tank in the loft above the hot water cylinder and a pump at the heating boiler

thanks for all responses

 

[Hugh Jaleak]

Can you have HW on without CH, but not CH without HW?

Looking at that cylinder, you have a fairly ancient setup, I agree with Stem, and would have to question if it's ever worked properly. Gravity Primaries, (flow and return pipes from boiler to cylinder), need to be a minimum of 28mm diameter for a gravity system, 15mm is just not going to transfer enough heat, which may be your issue....

Basic premise is, boiler heats the water, which flows up to the cylinder by gravity. Some control was used in a few cases with a 'C' plan system, by use of a cylinder stat and motorised valve on the Primary return pipe, but this was quite basic in the grand scheme of things. If CH was required, the pump was simply switched on to move heated water from the boiler around the radiators.

What is the small copper cylindrical item in the last pic connected to?

 

[JimCrow]

@Hugh Jaleak
It's a Willis immersion heater connected to the dhw cold feed and the hot water draw off.

 

[NewhouseOldhouse]

Considering this is an old setup apart from a new CH boiler what else would be required to upgrade the system?

Would a mega flow system be possible?

 

[Deleted member 267285]

Considering this is an old setup apart from a new CH boiler what else would be required to upgrade the system?

Would a mega flow system be possible?

That can only be answered by a visit from an G3 registered engineer, unless you could provide pressure and flow rates with additional testing? Only advice we can give to upgrade is changing layout to an s plan or y plan (zone valves, thermostats and trvs)

 

[NewhouseOldhouse]

That can only be answered by a visit from an G3 registered engineer, unless you could provide pressure and flow rates with additional testing? Only advice we can give to upgrade is changing layout to an s plan or y plan (zone valves, thermostats and trvs)

Costly?

 

[DP]

Considering this is an old setup apart from a new CH boiler what else would be required to upgrade the system?

Would a mega flow system be possible?

There is me under the impression that HW cylinder should be upgraded when boiler changed to be BC compliant. Lovely big radiator is that cylinder