Frost/Pipe protection

[Lecky]

Hello,
Apologies if you get asked this question all of the time but I'm trying to get the answer to it for my specific installation.

I'm planning to go away soon and due to the cold weather I'm trying to prepare the house as best I can. My intention is to have my central heating running for the same time as we normally have it when we are at home, i.e on between 6am and 7am, then 17:30 to 21:50 daily. 3 bed mid terrace house, 1 bathroom, 1 downstairs toilet. TRVs on all the rads bar the bathroom / downstairs toilet set to No.4 (of 6). No room stat.

Baxi Solo3 Boiler with an adjustable setting on it (1-6) currently set to 6. Megaflow CL145 hot water cylinder. Im pretty sure its an unvented indirect system as there is a pressure vessel in the airing cupboard. No tanks appear to be in the loft.

Now my question is this. Is it safe to leave the heating running as previously described with the hot water off and the Mains Water switched off? I.e will turning off the water to the property have any effect on the heating system? I want to turn off the mains incase the boiler fails as unfortunately the rising main goes into the loft then back into the airing cupboard. I ran the heating today with the water off with no apparent problems however, when switching back on the water there seemed to be a rush of water in the pipe for 3-4 seconds (no taps were turned on when the mains was off).



Thanks in advance for any advice.

 

[SimonG]

Leave htg on and isolate mains cold. Should be fine.

 

[lame plumber]

get a rm stat for the long term, then just leave heating on and stat at 8-10 and you shouldnt ever freeze, leaving it on timed doesnt account for when heatings off and you have a really cold period and risk of freezing.

 

[Alanc]

Insulate pipework in attics, any draughty and cold areas.

 

[Lecky]

Many thanks for the quick replies.

lame plumber; if I maintain the temp at 8-10 in the house, my loft temp could be considerably lower hense my thought to turn off the mains therefore minimising the potential damage.


As an aside, on the tank is the warning below. I know this is to do with restoring the expansion bit in the tank if there is a fault, but don't understand why it advises leaving the water on?

WARNINGS
IF WATER ISSUES FROM THE TEMPERATURE/PRESSURE RELIEF VALVE ON THE
MEGAFLO HE UNIT. IF THIS DOES NOT RECTIFY THE
FAULT SWITCH OFF ELECTRICAL SUPPLY TO THE IMMERSION HEATER(S) OR
SHUT DOWN THE BOILER. DO NOT TURN OFF THE WATER SUPPLY. CONTACT A
COMPETENT INSTALLER FOR UNVENTED WATER HEATERS TO CHECK THE
SYSTEM.

 

[lame plumber]

looks like an unvented cyl to me and you say no tanks in loft so any pipework on heating side should be circulating when on plus it should be insulated. good idea to turn off cold main to prevent continuous flooding should a leak occur. if you worried leace stat on 12 house warm enough to not freeze. but you said you dont have a rm stat in intial post

 

[Mike Jackson]

The label is recommending leaving the water on in case of a discharge in case the discharge is because of an issue with over heating. If the water is turned off and the heat source is still working the water in the cylinder could boil and steam would be discharged from the valve.