Excessive heat loss from system

I have a Systemate III system installed in my flat, and the heat it gives out into the room seems particularly excessive and has made the whole flat unbearably hot during the recent hot weather. It also means the system is calling for heat from the boiler very frequently as presumably it keeps dropping below temperature. A recent plumber visit determined (with the help of the Gledhill helpline) that the settings are reasonable (water temp at max 68deg C, min 61deg C).

Despite this, the expansion tank is almost too hot to touch and the water inside is the same, and also some of the pipework is too hot to touch. The cylinder itself is just warm. Neither the pipes nor the expansion tank have any insulation. Does this just sound like I need to lag the pipes and expansion tank, or is something not right?

Hi kd,

I would not expect the expansion tank on top to be hot in normal use. Warm perhaps but not HOT. It's probably overfilled - this will allow the very hot water in the store below to thermosyphon up into the expansion tank, causing the problems you describe.

Make sure the water level in the expansion tank is no higher than the water level mark (the ring embossed in the side of the tank). You'll probably have to bale out some water with a jug or something.

The pipework should not be hot all the time either, although it will be hot for a proportion of the time. Hot pipework in the airing cupboard is supposed to be insulated anyway so this will not be a major contributor to the problem. If there really ARE pipes hot all the time, check your gas boiler thermostat is set to MAX. This willl allow the Systemate to control the boiler and turn it OFF when necessary, otherwise the boiler runs 24/7.

Cheers, Mike

Hi KD, Mike

I have exaclty the same situation. I also have posted about thsi before. I have now changed out the three way valve. The System pump and also a circuit board as I noticed a chip looked blown. I am still getting teh same issue in this warm weather my system is hot to touch and also the pipework in the airing cupboard. The boiler cycles a lot only for very short periods of time. The settings on the board seem fine. The boiler is set to max. System pressure is at 1 bar which is what it shows it shoudl be set to. Any ideas what it could be ?