System struggling

[JBuzz40]

We have a Worcester 30CDi boiler with a joule thermalstore 2.0 (gas and solar) with a Giacomini heat exchanger supplying hot water for our wet underfloor heating and our domestic hot water. It is a system we have inherited but one that does not seem to work as intended. The underfloor heating is on all three floors.

The issue is that none of the manifolds have mixer pumps so are fed directly from the thermalstore at a set temperature (45) with the domestic hot water being, in theory but not practice, heated by the giacomini unit to 67 degrees. We are in a hard water area, so unsure if the giacomini is just furred up and hence isn’t able to heat appropriately? Or whether there are other options to ramp up the UFH water temp to domestic temp and supply at a rate sufficient for a bath/shower.

The thermal store is on the first floor and as I understand it, the suspended floors could/should be heated to 50 with the ground floor at 40? I have asked some local plumbers but many seem daunted by it.

I have been looking at options to provide us with more reliable hot water - baths and showers are rubbish.

1) Mixed sets on the actuator manifolds and run the thermalstore hotter - 65 perhaps

2) Remove thermalstore and replace with a unvented cylinder and then again mixing sets

3) Chelmer (designed the system) produce an ecocat boiler (combined hot/warm) tank that drops temp for UFH but suppliesat full temp for domestic hot water.

None of these options is remotely cheap and I want to get it right so would be grateful for opinions from people on here as well please. Especially if anyone has one of these set ups that works well

Thanks for your time.

 

[SimonG]

How is it controlling the water to 45 to the underfloor heating manifold?
Your set up sounds like a legionella breeding ground.
Your thermal store wants to be at about 85 - 90.
Mixer valve on outlet of plate heat exchanger to set dhw temp.
Supply thermal store water to underfloor manifold with mixing control on manifold.

 

[JBuzz40]

How is it controlling the water to 45 to the underfloor heating manifold?
Your set up sounds like a legionella breeding ground.
Your thermal store wants to be at about 85 - 90.
Mixer valve on outlet of plate heat exchanger to set dhw temp.
Supply thermal store water to underfloor manifold with mixing control on manifold.

There are no blending valves on the manifolds so the temp out of the thermalstore is what’s delivered to the UFH.

Presumably if I get the thermalstore up to 90 and then have the blending valves set to 40/50 on each floor that should do the job?

Is there any benefit of a dual coil invented over the thermalstore? Have been told it’s a much better set up but the quote doubles the price of just putting blending valves on each manifold.