Outdoor Boiler Anti-freeze

[feebeebos]

Hi,

I am fitting a Grant Out-door boiler and having just been in PTS and gasped at Fernox Inhib & anti-freeze price, £19 for 5 ltrs and you need 25% to protect down to -11 was wondering is automotive anti-freeze be alright to use? Car engine coolant works in a harsher environment with all different metals and probably higher temps.

Your thoughts appreciated.

Regards

 

[tomy]

A frost stat maybe !!!

 

[wilhelm]

closely followed by a pipestat.

 

[bripl]

proper insulation frost stat linked to a pipe stat wait till you see the price of 25mm armaflex the fernox is a gift in comparison

 

[2sheds]

I have one of these boilers myself and contaced Fernox t ask why their antifreeze is so expensive.

It was explained to me that automotive antifreeze is in no way suitable - if you have a leak in the immersion heater coil the water from the primary circuit can get into the domestic hot water.

Automotive antifreeze is highly toxic.

 

[feebeebos]

Thanks for the replys chaps.

Hadn't thought of the valid issue 2sheds raised, will definately not use automotive anti-freeze and will go the pipe stat route with the onboard frost thero.

Cheers

Dave

 

[2sheds]

My own boiler is a Grant outdoor module type. I think if you're fitting one of these it probably has a froststat already built in - mine certainly has.

Seemed to work fine last winter though I did burn quite a lot more oil than with our previous conventional indoor boiler.

I'm currently trying to find a way to reduce this consumption (you can see my earlier post).

 

[feebeebos]

Thanks for that 2sheds.

A thought occurred to me, don't get many of them!!

The scene, bitterest winter for years, -10 ootside and freezing wind, power is cut off, whats doing to protect the boiler?

I'm now thinking to spend £120 on sufficient antifreeze to protect down to say -15, could then dispense with frost-stat that Grant provide and anti freeze will pay for itself in reduced fuel bills!

What do you think?

Regards

Dave

 

[oilman]

The common auto antifreeze is ethylene glycol, the non-toxic type is propylene glycol, this is also used in high tech/performance/price etc engines so it is also used in the auto world. There's a long discussion about it a couple of years ago on the forum.

It depends where you are, but it's very unlikely you will get -10 and no electric for long enough to let your system freeze. Another way would be to buy a cheapie generator (you need only 500W) to run the heating system.

 

[2sheds]

Dave,

I'm no professional but speaking as a layman cannot see anything wrong with your idea about put in enough antifreeze and do away with the froststat. Perhaps someone who is a professional can point out the flaw.

I reckon that last years (mild winter) heating cost for our well insulated 3 bed bungalow was some £580 which was £200 more than previous year. (although a large part of this is of course due to the price increase in oil).

Do you know that 30 litres (which is what you would get for £120) is 25% of the volume of water in your heating system?

Mike

 

[MeMyselfAndI]

don't forget the frost stat is not only going to protect the boiler but the rest of the internal services by bringing on the heating. you could consider 2 stage protection, bring the circ pump on first say @ 5 degs, you try freezing moving water then boiler @ 0 degs...... just a thought

 

[feebeebos]

Many thanks for all your input.

I have decided to add enough antifreeze to negate the need for a frost or pipestat with the cost being recouped from lower fuel bills throughout the winter months. On each annual service the sg can be checked just as in a car, to ensure suffuicient anti-freeze concentration.

Will keep you posted on how it progresses.

Regards

Dave

 

[COG]

Is your Grant a system boiler or a combi , if its a combi then a frost stat would be recomended as with only anti-freeze you would have no latent heat to protect the mains water pipes at least with a frost stat it will come on and heat the w/w heat ex plus have you bugeted for replaceing the a-f each time a repair is made

 

[feebeebos]

Hi,

It's a open vented system boiler. Will build in a few valves to enable boiler to be isolated should the need arise. Can't use a freezer which will be a bit of a blow but that's the only real drawback I can see in using anti-freeze.

regards

dave