I have installed Hive but I want to improve the frost protection because there are lagged pipes in the loft which is much colder than the house. Does anyone see any reason why I should not connect the froststat across the 'live' and 'CH on' terminals on the Hive backplate? This should mean that the CH would come on when the froststat is activated regardless of the Hive setting and therefore protect the pipes in the loft. The CH would of course remain switched on until the temperature in the loft rose sufficiently to deactivate the froststat regardless of the Hive roomstat setting. There are radiator valves elsewhere and a bypass installed so presumably this should not cause a problem with the boiler or the heat levels inside the house.
Hive frost protection
- Thread starter Romo47
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- frost hive heating
Is the house lived in? Where in the uk are you? I cannot see anything happening (85% of the uk)unless we suddenly get an artic winter. THis is assuming that you actually use the system and any header tanks arn't right at the very top of the apex. Remember if they are down low then there should be no lagging underneath and a decent jacket fitted. I did get caught out once, wasnt a burst pipe, it was a house I purchased over xmas and didnt work on it the storage tank in the loft iced over and activated the ballcock. Went round in the new year to find a frozen internal wall with sheet ice on it where it had run down the wall 
Turning the heating on won't do anything for that, unless your loft is so poorly insulated that heat from the house results in the loft temperature rising significantly.
As above - unless the loft is poorly insulated, the temperature up there may never get above the frost stat setting, the result being that your house will become ridiculously hot as the heating would be on all the time.
Romo my comments were for others following a thread you have already stated that you have insulation. Your header tanks if lagged correctly will not freeze assuming you are using the house (ie not left empty and unheated for days on end). As you have insulation running the system downstairs to a level to stop potential of freezing in the loft is just crazy. Sorry not sure where this idea has come from for someone in the UK.
never done it but if you are worried about the temp in the loft I suppose you could install a frost stat and get it to switch to a small electrical heater of some description.
That would be the normal way to do it, with the provision that your existing wiring to the Hive contacts is 230V and not the 24v used by some boilers.
The problem would come when the temperature drops, the frost stat turns 'on' and if it is a prolonged spell of cold weather the Hive will be completely overridden and the frost stat may keep your heating on 24/7. Then, if, as it should be, there isn't a radiator with a TRV on in the room where the Hive thermostat is located it's gonna get pretty warm in there; especially if all of the other TRV's are closed.
To prevent this happening, the frost stat is normally wired in series with a pipe thermostat set to about 20 degrees, and fitted to one of the return pipes at risk. This means that the circulating water in the pipes is kept warm enough to stop the pipes freezing, and radiators at 20 degrees won't overheat your house.
However, as the tank you refer to is for cold water, heating the house below with a frost stat and hoping sufficient heat permeates through the insulation into the loft to warm it, is a bit unreliable, and it probably wouldn't add anything more that the normal heating of your house does on daily basis anyway. In this case ianmcd's suggestion would probably be a better idea. Make sure you get a suitable electric heater though like a tube heater or similar so that it doesn't pose a fire risk.
I have to say that I have a 4 gallon F&E tank right up in the apex of my roof. It's been there 20 years and has the standard plastic bag and rockwool type jacket on, not had a problem to date. Been up a few times when we've had -10 degrees for a few days, to check it, but have never seen any sign of ice. The cold water feed pipe is extremely well insulated though, as that is more likely to freeze having less water in it.
Many thanks to everyone for their very helpful replies. I should explain that the vulnerable tank is the CH header tank which is in the apex of the loft. My theory was that this would be protected by internal water pipe circulation when the CH is switched on (the water in the header tank is normally warm in such circumstances). However, I share the concerns of most others about the consequences of the boiler always being on if the frost-stat is activated. Stem's idea of the auxiliary pipe thermostat would solve this problem provided a suitable circulating pipe can be found nearby – something I would need to explore. Finally, does anyone think there is likely to be an issue with the Hive processor electrics if the 'CH-on' terminal is made live by the frost-stat rather than by the processor itself?
you are not listening to all the correct advice that you have been given, heating your house will not heat a well insulated loft, the pipe stat system that stem refers to is to protect a heating appliance in an area likely to freeze, garage, basement ,loft etc, it will not protect your pipes and tanks in the loft
I wouldn't expect so. The Hive works in the same way as all other programmers, and what you propose is the only way to connect a frost thermostat, so I can't believe that wouldn't have been a consideration, but if you are worried ask them. Only they will know how the internals are configured.
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I appreciate the point but as I said the water in the pipes and header tank is warmed by a degree of internal convection when the CH is on thus reducing the chances of freezing.
In reply to stem I tried but they didn’t want to advise.
well you asked for advice and everyone has given you the correct advice , another one that only wants to hear the answer that agrees with them, it will not work, but go ahead and do it
Not a very good helpline then is it!
I would be fairly certain it would be OK and would expect the terminals to be connected to relays as other programmers are. Odd they don't want to help though.
Thanks for all the advice: I shall now reflect on what to do – whether to forget about the idea and possibly install a supplementary electric heater triggered by a frost-stat or to try the frost-stat/Hive combination augmented by a pipe-stat to moderate the internal house temperature.