Retro Fitting Frost Stat

Randyleprechaun

Hi all,

Just wondering what are peoples opinions on how to wire up frost protection on existing installations ie. oil fired boiler external or in external garage/shed. Controlled by single channel clock in house and pump and boiler powered from same 3 cores in a JB. 4th core usually available for permanent power, just not used yet. I am asking this question as alot of people are going to be adding in frost protection to their systems in the near future.

I'm wondering what people do, do they:

Wire it in such way that all the heating is on when stat kicks in.

Use 2 stage protection(adding more cost)but saving on fuel, and not heating house as much.

Wire it that it only controls the circulating pump(not straight forward in a retro fit, may require extra bits and bobs that folk may not be willing to pay for)

What are your opinions

When asked to install a frost stat for someone, should you only worry about protecting the external boiler/piping and not worry about piping in the house to rads etc, or should you be looking at protecting the whole lot.

Bruthal

Its a good question alright. Maybe a frost stat bringing on everything and the frost stat is wired through a pipe stat at the boiler return set at 20 or 30 degrees just so it is running low when only brought on by the frost stat.

I wonder is antifreeze an option. Fernox/inhibiter combination could be used in heating systems maybe?

M cebee

i'd think switch on the CH prob through a pipe stat on the return -for a basic system

http://www.uk-plumbing.com/fernox-alphi-11-5-litre-antifreeze-p-2290.html
anti-freeze is prob expensive enough


bringing on the pump will circulate water but the house will freeze

frost stat location ?

Bruthal

The inhibiter on its own is nearly that price i think. Did you put some in your own system when you refilled it? Dont forget that.
Frost stat location outside somewhere id say would do?


Maybe a couple of bottles of vodka in it would stop it freezin:D

M cebee

i didn't put inhibitor in yet-but i'll drain a bit off and add it to header tank when i get time-i might add a rad yet to en-suite

the boiler in outside shed is a tricky one -you have your house,boiler and underground pipework

i reckon outside frost stat and pipe stat on return maybe-i can't see how any internal frost stat is failsafe for these(if there's no anti-freeze in system)-could be wrong though

Randyleprechaun

So if you had a boiler installed in an external garage/shed, would you mount the frost stat beside it with a pipe stat on the return to keep temp low. This would protect the boiler if temp. in garage/shed became freezing.(Apologies M Ceebee, you had answered while I was writing this post)

Or, would you mount the frost stat outside with pipe stat again on the return.



What if the boiler was one of the heat pac installed externally?????

Again, it begs the question, are you protecting the boiler only, or the boiler and all the piping etc.

I'm asking these questions because I've seen lately that people want the protection but they aren't willing to do it right ie. pay the price. then if you just throw a frost stat on the boiler that brings everything on, they don't want to pay for the excess oil used!!!!!!!

M cebee

the stat in the heatpac may not be enough to protect house-they prevent the boiler freezing and may not even heat house on some systems

Randyleprechaun

M cebee wrote: »

the stat in the heatpac may not be enough to protect house-they prevent the boiler freezing and may not even heat house on some systems

So it only protects the boiler and one would assume that all the piping etc should be lagged enough. That's how I always viewed this anyway. If I was asked to put a frost stat in for the boiler then thats exactly what I'd protect and nothing else. A frost stat mounted internally in the heat pac or mounted on the wall beside a garage/shed boiler.

Seems like the pipe stat and frost stat might be the best combination, ie comes on at freezing but only heats system up enough to keep warm and not roasting hot.

It's atricky one isn't it....one of these things thats down to your own interpretation

M cebee

for outside boilers maybe ya outside frost stat and pipe stat
(if you're keeping it basic)

-keeps boiler running low in cold weather

indoor boiler -i think it's just a stat in coldest part of house


there's no single solution for all cases

Bruthal

Would have to get zone motorised valves to open as well on systems where they are fitted. A relay or 2 fed through the frost and pipe stats could power on the motorised valves so the relays would keep them electrically seperate during normal operation.

If the heating was up and running with occupants in house then the frost stat would have no effect if its frosty out as the pipe stat would be open with the heating in normal use, except in the first few minutes of heating up anyway.

Over all you would think the anti-freeze has to be an option to considder too though.

Bruthal

M cebee wrote: »

i didn't put inhibitor in yet-but i'll drain a bit off and add it to header tank when i get time-i might add a rad yet to en-suite

Probably as well draining it down a fair bit and tie up the header stop cock float, then put the inhibiter in empty header tank and re fill. If you just put into header it could be a fair while before it is fully into the circulation of rads.

M cebee

ya

Buford T Justice

tbh, if you are going to put inhibitor into the system, drain it fully and get all the dirty water and sludge out of it first, then put in the inhibitor and fresh water.