Is it possible to have two heating systems connect to a gas boiler?

Hi,

I've recently just installed an underfloor heating system on my gas boiler but hit a snag with the control system. My previous system was a 3 zone wireless system (hot water tank, upstairs rads, downstairs rads), the hot water had a cylinder stat to cut off when water hit 60 degrees.

The snag is the system I've bought does not have either a wireless or wired cylinder thermostat option i.e. I can turn on my hot water but no control to turn it off when hitting a certain temperature.

Is it possible to wire my old system up to the boiler in addition to the ufh heating system and use the old controller just for the hot water?

Did you not ask about this before you installed the new system?

jpd said:

Did you not ask about this before you installed the new system?

Click to expand...

Do you have any insight to the question I asked?

How I arrived at needing to ask the question isn't relevant. However, I asked for a wireless system which I got but the hot water controller is not suitable for actually controlling a cylinder. So now trying to figure out options without having to open up ceilings and running a cylinder thermostat or similar.

Thats why I asked whether we can just connect up the original system alongside the ufh system to control only the hot water. In the new set up I still have upstairs rads and hot water, then downstairs ufh split into 3 zones.

You could have the two controll systems operating in parallel.
The gas boiler would then run if either or both systems called for heating.
It's a simple electric circuit. Two separate parallel switches switching the same load.

S class said:

You could have the two controll systems operating in parallel.
The gas boiler would then run if either or both systems called for heating.
It's a simple electric circuit. Two separate parallel switches switching the same load.

Click to expand...

Thank you, that seems like the best solution. Assume that means I can run the heating and separate hot water control at the same time?

The other option is to just run the hot water tank of the emersion, but assume that will be costly.

DublinHead54 said:

Thank you, that seems like the best solution. Assume that means I can run the heating and separate hot water control at the same time?

The other option is to just run the hot water tank of the emersion, but assume that will be costly.

Click to expand...

Yes you could have either system calling for heat separately or both calling at the same time.

S class said:

Yes you could have either system calling for heat separately or both calling at the same time.

Click to expand...

Thanks, another question. Do I need to have a thermostat on the boiler? The system did come with a HW stat, it just doesn't switch off once the boiler has gotten to 65 degrees. However, it has timing functions, so could I just use that to come on for 30 minutes to heat the water and then switch off. There is no risk that the water will continue to heat?

DublinHead54 said:

There is no risk that the water will continue to heat?

Click to expand...

The boiler will have an in-built thermostat that will turn off the burner while still powering the circulation pump once the water reaches a set temperature. It'll only switch back on the burned once the temperature of the circulating water drops below the threshold.

One thing you need to check though, underfloor systems usually run at lower temperatures to radiator systems. Is that the case for yours and if so, will that temperature be enough to heat the water tank sufficiently?

Leo said:

The boiler will have an in-built thermostat that will turn off the burner while still powering the circulation pump once the water reaches a set temperature. It'll only switch back on the burned once the temperature of the circulating water drops below the threshold.

One thing you need to check though, underfloor systems usually run at lower temperatures to radiator systems. Is that the case for yours and if so, will that temperature be enough to heat the water tank sufficiently?

Click to expand...

I think so as the system has a hot water wiring port separate to the ufh zones, the missing part is just a cylinder thermostat. Good to know on the boiler as well. There is also a temp regulator on the ufh manifold which can be set to different temperatures, I am assuming this means ufh can be one temp and the feed to the boiler be another. Who knows, the information out there is surprisingly lacking!

Per previous poster - the UFH manifold should have a bypass valve to enable the UFH water temp to be set. Typically around 35 degree C