Static caravan combi ....

[Jim GM4DHJ ...]

Got my first static caravan with central heating earlier this year and never thought about the frost protection function until this morning when there was a noise coming from the combi, it is freezing this morning here in south Airshire. It wasn't the noise of the extract you hear on over run is was a quieter noise. I am a bit worried because when we leave our van we always turn off the gas and the water and obviously any frost protection won't work. We just renewed the antifreeze in the radiator loop and was wondering was the noise the frost protection and should we leave the power and gas on when we are not here in cold weather ? .....and does the frost protection just protect the coils of the hot water system? .....

[harry]

Turning off water to protect against frost won't help. You have to additionally drain down any part of the system not protected with antifreeze. ie hot and cold water. There's probably a drain off valve somewhere to do this.

[harry]

Additionally, when draining down, open all taps to get as much water out of the system as possible. If it's properly designed, there should be no/negligible water left in the system after draining down.

[Jim GM4DHJ ...]

yes we do that at the end of the season but not the radiators because we have antifreeze in them ...it is when we are using the van and coming and going in frosty conditions I am worried about ......I turn off the water in case of a bad joint etc not frost protection ....

[John Rumm]

Is it a condensing boiler? If it is, is the condensate drain protected from freezing?

(Its a common failure mode where boilers have been installed without following the manufacturers guidelines on protection of the drain).

[Jim GM4DHJ ...]

no

[Brian Reay]

Is the system one designed for caravans or a domestic one?

Domestic ones (generally) have a 'frost stat' which will turn the system on if the temp goes too low to prevent damage, obviously you need to leave the gas and electric on for this.

Another idea, just leave the heating on 'low', perhaps 10 degrees or even less, this will also help protect other water systems.

I'm not familiar with water filled caravan heating systems - although I know they exist- our motorhome has ch but it isn't water filled. I drain the water tank etc and leave the taps 'on'. If it is very cold, I put the electric heater on low (we keep the mh on the drive), more as damp prevention, although we've never had an issue.

You could consider a 'Hive' type system (assuming you have internet at the caravan). Then you could monitor the temp locally via your phone and turn the heating on when needed. That would be easy if the system is similar to or at least as easy to control as a domestic, perhaps 'single channel' (no hot water) domestic system.

[Jim GM4DHJ ...]

no diference other than it works on Propane rather than domestic gas.......

yes but this morning there was a noise from the combi but no extract fan on the flue was running......and yes I would expect gas and lecy to be on for this to work....it is just that we are used to switching off the gas when we leave and probably should leave them on in cold weather like this......

can't afford the propane.......and a static caravan room has two permanent vents high and at least one in the floor ......

anyway Wednesday is the end of the season and the system will be drained except for the CH loop which has just had anti freeze pumped into it......which is all very well but some expert on site said leave the lecy on because the combi pump will fire up during a period of non activity just to circulate the CH loop.....didn't believe him but who knows?

going to read up about this specific boiler this evening......

[Jim GM4DHJ ...]

Worcester 24i .

"If the boiler main board detects a temp below 8 deg c it starts the pump until the temp rises above 9 deg c, the action of the pump is enough to heat up the boiler in mild conditions. if the temp continues to drops below 5 deg c the boiler fires till it gets to 20 deg c then shuts down."

that explains it then ......only the pump was on this morning .......not the boiler firing up ......bloody cold this morning....I will know what is going on tomorrow ........

[Jim GM4DHJ ...]

but then again that is pointless because the van CH pipes are full of anti freeze unlike a house system .........

[Jim GM4DHJ ...]

but then again if the action of the CH pump heats up the boiler..........

[Jim GM4DHJ ...]

up for a pee at half three and the pump was running it was about 7 deg.....got up at 7am and it was still on so ran some hot water to heat up the combi and it went off......happy now........

[Jim GM4DHJ ...]

always happy when I know how things work ...except for radio where it would spoil the mystery and fascination of it all...

[Brian Reay]

So much for your boast that you have more money know what to do with. Sounds more like 'Penny wise, pound foolish.' You will look silly when it freezes for the sake of a few pounds worth of propane.