External boilers & frost protection - do you have a pipe stat fitted?

ilikecookies

Hoping for some wisdom from folks with external boilers which are sited directly outside (eg. in insulated boxes) rather than in unheated spaces (eg. garages, boiler houses, etc).

We recently had a Grant Vortex PRO fitted outside the house: it is installed flush against an external wall with the pipes running directly into the house through the wall (ie. no pipework is exposed per se outside).

Just lately the boiler has started to fire up every so often for 15-20 mins when the programmer is set to off so I assume this is the internal frost stat in the boiler kicking in as the outside temperature has been in the 4-5 degree zone.

Each time it switches on the rads get warm which I assume is because we don't have a bypass.

Whilst of course I don't want the boiler to freeze I'm concerned this constant on/off may be a little wasteful especially when the outside temperature is around 4-5 degrees. I spoke to Grant and they said they did not recommend turning down the frost stat and proposed either creating a bypass (so the rads don't get heated) or fitting a pipe stat.

I assume that fitting a pipe stat would be more economical and wondering if anyone else had gone down this route and if so:

1) Where is the pipe stat sited - assume inside the boiler on the flow pipe?

2) How do you give the pipe stat preference over the integral frost stat in the boiler?

3) What sort of temperate should the pipe stat be set at?

Thanks in advance for any advice!

macman

The frost stat usually measures the temp in the CH flow circuit, which will start to freeze at about 3C.
Therefore the default frost 'stat setting of 5C is doing it's job and preventing an expensive freeze up.

welda

Ditto with macman, I have similar setup, in as best as I can insulate outside boiler house, my pipe stat is situated close to boiler on the return. I imagine there may be very little space in your setup?

Regarding where the heat goes, personally, if boiler kicks in due to excessive cold, I prefer any heat to go into the house, rather than a bypass loop.

Regards....