My Vaillant turbomax boiler has been moved to the loft this year. So in winter it will be subject to very low temperatures. What precautions should I take to avoid problems ? It will obviously generate its own heat, but if it switches off (it has an intermittent problem that needs a power cycle to reset), it could freeze up I suppose. My initial idea was to build an insulated box/cupboard around it to take it inside the heated envelope, but that might be overkill.
Simon.
Add an antifreeze to the circuit?
That reduces the risk - but if it's a combi, obviously that still leaves the potable water unprotected?
Have you checked to see if it has a frost setting built in? Some have and will fire up to prevent them freezing even if the system is set to off.
Consider putting it on a 24hr timer with a 20? minute off cycle. This will give you a daily reset. I do this for security lights which can stay permanently on if the mains fails for a short period of time. You can give multiple daily resets this way if necessary.
Not sure that dropping the power on a regular basis is a good idea - it may defeat pump run-on and cause localised overheating if dropped in the middle of a burn.
Of course, boilers survive the odd mains failure - but not every 24 hours.
Personally, I'd be looking to fix the boiler so it does not keel over.
A frost stat should keep it OK, though I would get that need for a reset sorted.
Richard
About 10 years ago I fitted my boiler and megaflo in the (attached) garage, so had the same concerns. The boiler is mounted on 18mm ply that's insulated from the wall with a DPM and 50mm of insulation (the boiler is actually fixed through the ply into the battens). I chose a boiler with an internal frost stat and bypass but also fitted external (adjustable) ones; the external stat is fixed to the board, next to the boiler. All the pipework is well insulated. None of this will help if the boiler fails so, if that bothers you, fit a small sealed bar heater beneath the boiler and control it via a frost stat.
If you build a box make sure to meet the boiler-manufacturer's clearance and ventilation specs
Valid point,
Agreed.
The boiler is old and will need replacing at some point, so I'm not too wor ried about the power cycling, which is actually only once every few days. T he fault is when the heating has been on and the hot water is used, then wh en the boiler drops back to the heating, it decides the primary circuit is "dry" and faults out.
I think the "dry" detection is done by two thermistors, one either side of the primary heat exchanger. If the difference in temp is too high it thinks there is a lack of water running through. The thermistors have been change d by the plumber-in-the-family (gassafe) (actually I need to confirm that), but occasionally the fault still occurs. There is a reset sequence on the boiler but I cannot do that remotely, so I have a webmin wireless switch an d use that to power cycle when it happens. When the fault happens the unit is dropped stone dead as it thinks there is a safety issue, so power cycling then does no further harm.
Of course if there was really a saftey issue, the fault we reoccur on power
-up, but it never does ! Ideally the problem would be fixed but we have tri ed. Anyone got any ideas ? There does not seem to be air in the system, but I suppose the heat exchang er efficiency could be comrpomised (we have run descaling through, etc).
Simon.
From the installation guide: The clearances are as detailed below and are shown on the installation template supplied with the boiler:
- 150 mm below the boiler
- 5 mm on either side of the boiler
- 210 mm on top of the boiler
- 500 mm in front of the boiler*
No problem there for boxing then. My boiler is on plywood on a 9" solid brick wall, no insulation behind it - I'll probably do an insulated cupboard. Good plan about the tube heater though. I have a double socket just below the boiler so it could be put in there. Do the tube heaters come with a built in thermostat, or just a power control ?
Simon.
How about connecting the pump to a frost stat?
And heating tape over the hot water pipes?
Some time ago the pipes in my attic did freeze. I did not start the boiler, which is in the kitchen until I was sure that water in the pipes had thawed. Fortunately there were no leaks possibly because the pipes are mostly copper and might stretch a bit.
These days I have a frost stat it the attic. I have known this to switch on even when the house is heated normally.
Copper pipes are very likely to burst if frozen. Plastic pipes the least.
You were lucky.
That's a pretty nice idea - even if the boiler is malfunctioning, circulating the water will help as the rest of the house will be warmer than the attic even if unheated.
Of course, whether you can do that if the pump is integral to the boiler is another matter :-|
Careful - they aren't factoring on you making a small insulated enclosure - more like a regular kitchen cupboard.
If you made a bigger enclosure, more like an airing cupboard, that might be OK.,
Have a look in RS and Farnell for "intrinsically safe heaters". Or zig zag some heat tracer tape (for pipes) around the inside of the cupboard as that is the same idea. If you do insulate the cupboard you probably only need in the order of 100W to make the difference.
Yes, the sides would be quite tight up to the boiler (say 30mm), but the enclosure would be from the floor (to enclose the pipes) to above the boiler flue exit. So a bit like an airing cupboard. Point taken about overheating as well as underheating though !
Simon.
But how do copper and steel compare?
The cold feed is steel and there may be some more.
The antifreeze should work if all else fails! Turning of the mains would reduce the risk of water damage.
I would think the OP's main risk is if he leaves the house.
If he is in the house he would be aware of the boiler's failure and could put a blow heater in the attic.
There should be a frost stat somewhere nearby to fire the boiler for a while if the ambient drops to 4C or lower in the loft.
Insulate all pipes up there that have water in them generously.
Unlikely unless there is a draft playing on bare metal or it is left for a very long time with external temperatures sub zero and a penetrating frost. I saw a flat fail that way once.
I am intruiged as I was recently advised by a Oftec engineer that my existing oil boiler which is in the (floorboarded part of) the loft is no longer acceptable practice - I think he said due to fire regulations.
There is also the problem of finding a drain for the condensing boiler. I have my suspicions they just don't want to drag it up the stairs!
Even if internal I would be surprised to find one wire to the pump wasn't connected to neutral and the other end connected to a relay, either mechanical or solid state variety.
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