Hi, I've just googled 'Heatmiser not working' and found your post from 2011. I don't even know if you're still active on this website, but thought it worth a try.
I've got a similar problem now: I've had a wet underfloor heating system installed with the UH1-W Heatmiser control system and wireless thermostats. The hot water is provided by an air-source heat pump (ASHP). When I turn a thermostat up in one of the rooms it takes ages for the flow pipe to the manifold to begin to warm up, and then even if I'm lucky enough for it to actually get hot, within about half-an-hour it goes cold again.
The ASHP installers have been back to check their system, and say it's ok. The builder who installed the underfloor heating has had a breakdown (!) and other than sending a plumber to confirm that the pipes have all been connected properly, is doing nothing to help.
I wonder if you solved your problem, and if so, how?
Keeping my fingers crossed that you're able to receive this message!
Liz
I've got a similar problem now: I've had a wet underfloor heating system installed with the UH1-W Heatmiser control system and wireless thermostats. The hot water is provided by an air-source heat pump (ASHP). When I turn a thermostat up in one of the rooms it takes ages for the flow pipe to the manifold to begin to warm up, and then even if I'm lucky enough for it to actually get hot, within about half-an-hour it goes cold again.
The ASHP installers have been back to check their system, and say it's ok. The builder who installed the underfloor heating has had a breakdown (!) and other than sending a plumber to confirm that the pipes have all been connected properly, is doing nothing to help.
I wonder if you solved your problem, and if so, how?
Keeping my fingers crossed that you're able to receive this message!
Liz