Glycol - Maintenance?

[anonymous]

Heya 

 

So I imagine that glycol is less risky than antifreeze valves? Though it surely degrades over time 

 

What kind of maintenance would be required? I'm guessing that glycol isn't "set it and forget it", ditto for anti freeze valves? 

[sharpener]

Annual HP maintenance will include checking the glycol concentration with a refractometer.

 

Don't know about chemical degradation but if it incorporates inhibitor I would imagine a life of many years just like water with inhibitor. Also the HP does not reach the same temps as a boiler.

 

Some mfrs have warnings (no idea if anyone pays any attention) about dissolved oxygen, pH and hardness e.g. Vaillant Arotherm Plus - but the following appears actulally to have been cut-and-pasted from a boiler manual. pH 8.2 is quite alkaline, mains drinking water pH only has to be >6.5:

 

 

[anonymous]

12 hours ago, sharpener said:

Annual HP maintenance will include checking the glycol concentration with a refractometer.

 

Don't know about chemical degradation but if it incorporates inhibitor I would imagine a life of many years just like water with inhibitor. Also the HP does not reach the same temps as a boiler.

 

Some mfrs have warnings (no idea if anyone pays any attention) about dissolved oxygen, pH and hardness e.g. Vaillant Arotherm Plus - but the following appears actulally to have been cut-and-pasted from a boiler manual. pH 8.2 is quite alkaline, mains drinking water pH only has to be >6.5:

 

 

Thanks. I take it that glycol is way less risky than anti freeze valves? 

[sharpener]

41 minutes ago, anonymous said:

Thanks. I take it that glycol is way less risky than anti freeze valves? 

 

No personal experience (as yet) but I do not like the idea of returning after a winter break to find house cold and HP inoperable because water has been dumped to drain. Or finding the valves were stuck shut and the HP is a write-off. Cost is about the same order anyway.

[JohnMo]

1 hour ago, sharpener said:

 

No personal experience (as yet) but I do not like the idea of returning after a winter break to find house cold and HP inoperable because water has been dumped to drain. Or finding the valves were stuck shut and the HP is a write-off. Cost is about the same order anyway.

They were my thoughts also. Plus if I was away, not sure the wife would know what to do to repressurise the heating system. All are reason not get unnecessary agro. You take a very small hit in CoP, for an easy life.

 

I would also doubt the plumber that comes along to service would have a refractometer. Would like be supposed when someone confirms there was checked.

 

However the degradation mechanism is generally oxidation and exposure to high temperature, non of which should be present in an ASHP system, which is low temperature and a closed pressurised system.

[TonyT]

If I had external pipework, I think I would have some trace heating as a precaution, controlled via a frost stat or self regulating type, prior to the insulation going on

[DanDee]

The flow meter/sensor needs cleaning as well.

 

[sharpener]

1 hour ago, JohnMo said:

I would also doubt the plumber that comes along to service would have a refractometer. Would like be supposed when someone confirms there was checked.

 

There seems to be some awareness to judge by recent postings on Heating Design f/b group. Someone else mentions the Fernox but it is well over £100 and looks just the same as the ones on Amazon which others swear by

 

 

1 hour ago, TonyT said:

If I had external pipework, I think I would have some trace heating as a precaution, controlled via a frost stat or self regulating type, prior to the insulation going on

 

Many have a crankcase heater for the compressor and some have trace heating for the condensate drain as well. But only as good as your electricity supply. I am just 200m from a substation but I would still prefer a passive solution.

 

Edited August 7, 2023 by sharpener