Filling UFH with antifreeze

[Omi]

Filling with water seems simple enough (just connect to a tap) but how does one go about filling the UFH pipes with antifreeze instead?

 

Would a simple 12V transfer pump do the job?

 

[Gus Potter]

1 hour ago, Omi said:

Filling with water seems simple enough (just connect to a tap) but how does one go about filling the UFH pipes with antifreeze instead?

 

Would a simple 12V transfer pump do the job?

 

 

 

The vulnerable points are where the drain cock is, drafts under where you may have a bit of suspended floor. Please don't fill it (UF) with antifreeze as at some point when you service the heating this will end up in the ground / sewer or local stream. If it gets that cold your other water pipes will burst long before the UF pipes which are insulated by screed?

 

 

 

 

 

 

 

 

 

[willbish]

8 hours ago, Omi said:

Filling with water seems simple enough (just connect to a tap) but how does one go about filling the UFH pipes with antifreeze instead?

 

Would a simple 12V transfer pump do the job?

 

I did mine this week using the power of gravity. Took a while mind! Longer than any jobbing plumbing would have tolerated.

I just rigged a funnel about 1.5m above the manifold and every time I walked past just topped it up.

Assuming you have a monoblock ASHP without a buffer as no other reason for glycol in the mix?

Edited October 30, 2021 by willbish

[Nickfromwales]

8 hours ago, Omi said:

Filling with water seems simple enough (just connect to a tap) but how does one go about filling the UFH pipes with antifreeze instead?

 

Would a simple 12V transfer pump do the job?

 

Is there anything in the pipes atm?

[Omi]

19 hours ago, Gus Potter said:

The vulnerable points are where the drain cock is, drafts under where you may have a bit of suspended floor. Please don't fill it (UF) with antifreeze as at some point when you service the heating this will end up in the ground / sewer or local stream. If it gets that cold your other water pipes will burst long before the UF pipes which are insulated by screed?

The UFH will be filled and screeded before winter. The build is still in the early stages and won't be occupied for a while yet so freezing over winter is certainly a possibility. A burst water pipe is probably a lot easier to fix than a busted up floor due to frozen UFH! We also don't have the water connected just yet so that's not a risk anyway.

 

13 hours ago, willbish said:

I did mine this week using the power of gravity. Took a while mind! Longer than any jobbing plumbing would have tolerated.

I just rigged a funnel about 1.5m above the manifold and every time I walked past just topped it up.

Clever - but doesn't that risk getting air bubbles trapped in the system?

 

12 hours ago, Nickfromwales said:

Is there anything in the pipes atm?

Nothing - we still need to lay down the system. Just trying to plan ahead.

 

Thanks.

[Nickfromwales]

16 hours ago, Omi said:

Nothing - we still need to lay down the system. Just trying to plan ahead.

 

Thanks.

Why the need for antifreeze? Are you winter prepping? Just dry test with air if you’re just needing to prove the pipes before install. 
If you’re just looking to treat the system at the point of commissioning then you just do that via the upper manifold vent / drain point with a 3/4” or 1/2” flexible hose and a funnel. Make sure the lower manifold air vent / drain are completely removed otherwise it’ll be ridiculously slow going. 

[Omi]

7 hours ago, Nickfromwales said:

Why the need for antifreeze? Are you winter prepping?

 

Yes - the build is still quite some way from getting completed and we're looking to have the pipes installed and screeded before winter.

[Nickfromwales]

18 hours ago, Omi said:

 

Yes - the build is still quite some way from getting completed and we're looking to have the pipes installed and screeded before winter.

Don’t fill with water then, simples! 
Buy the pipes in the correct length coils from Wunda and they’ll come sealed and pre-pressurised to a good few bar. Cutting into it gets quite a notable rush of air and associated hissing noise.

Either that or complete a regular installation with manifold rails and pressurise yourself / installer with air. A pressure gauge will show you that things haven’t gone tits-up during screeding  

[akjos]

On 30/10/2021 at 07:43, willbish said:

I did mine this week using the power of gravity. Took a while mind! Longer than any jobbing plumbing would have tolerated.

I just rigged a funnel about 1.5m above the manifold and every time I walked past just topped it up.

Assuming you have a monoblock ASHP without a buffer as no other reason for glycol in the mix?

@willbish are you running your UFH directly from the ASHP water pump? If so, any issues so far? And also do you know how the ASHP actually controls the pump?

 

I’m planning a similar simple system. Monobloc ASHP directly feeding UFH from internal pump without any buffer, zones or thermostat. Whole system one zone and weather compensated based on heat loss of the property (and also a three port valve for DHW but that’s standard). 

 

thanks

[SuperPav]

On 01/11/2021 at 15:13, Nickfromwales said:

Don’t fill with water then, simples! 
Buy the pipes in the correct length coils from Wunda and they’ll come sealed and pre-pressurised to a good few bar. Cutting into it gets quite a notable rush of air and associated hissing noise.

Either that or complete a regular installation with manifold rails and pressurise yourself / installer with air. A pressure gauge will show you that things haven’t gone tits-up during screeding  

 

Piggybacking on this thread as similar situation - we did a wet-fill prior to pouring the slab. The slab in the garage is now poured, looks like no leaks/damage, so happy days. However, there's probably 250lm of ufh pipe full of water in the slab, and the earliest that will get any sort of heat through it is probably not until March at this rate. Do I need to somehow completely empty the water out of it (compressed air onto the inlet of the manifold?), or could we just leave it but open the manifold so it's vented/can overflow?

 

I'm not sure the garage will freeze over (walls + roof in place), but it's certainly not impossible?

[Alan Ambrose]

One vote here for blowing the water out.

 

Alan

[JohnMo]

If you have water without antifreeze in the UFH, it could freeze, and if did you wish you had blown it out or filled with an antifreeze.

 

I remember a grand designs where a self builder had water in the UFH, a few freezing days, next thing was water escaping and the floor being dug up.

[Nickfromwales]

2 hours ago, JohnMo said:

If you have water without antifreeze in the UFH, it could freeze, and if did you wish you had blown it out or filled with an antifreeze.

 

I remember a grand designs where a self builder had water in the UFH, a few freezing days, next thing was water escaping and the floor being dug up.

Gravenhill, 1st of the 2 plots done iirc. Was a mess. 

[Nickfromwales]

3 hours ago, SuperPav said:

 

Piggybacking on this thread as similar situation - we did a wet-fill prior to pouring the slab. The slab in the garage is now poured, looks like no leaks/damage, so happy days. However, there's probably 250lm of ufh pipe full of water in the slab, and the earliest that will get any sort of heat through it is probably not until March at this rate. Do I need to somehow completely empty the water out of it (compressed air onto the inlet of the manifold?), or could we just leave it but open the manifold so it's vented/can overflow?

 

I'm not sure the garage will freeze over (walls + roof in place), but it's certainly not impossible?

Wet and dry vacuum to suck out the majority, and introduce some air pockets, and leave both ends of the loops just taped over loosely. 
With walls and roof on, you’ll be fine with that measure for mitigation. Is the garage door on, or can you OSB it to stop the winter wind blowing in / around?

[markocosic]

It's ethylene glycol that big a deal @Gus Potter?

 

It's fairly acutely toxic to critters; but breaks down quickly in the environment, no?

 

It goes in everything out here. Even the regular heating circuit. Not wanting it to freeze if the heating breaks down in midwinter. 😮

 

Mixing it with water already in pipes is tricky. You get slugs of glycol and slugs of water running around the pipes unmixed except at the boundaries. 

 

blasting or with compressed air probably easier that properly mixing in glycol anyway!

[SuperPav]

Thanks all, looks like blowing out/sucking out is preferred so will get that done this week.

 

The roof is on, the walls are on and partly insulated, the garage door is on, and the garage is full of stuff and has a 900W dehumidifier going in it, so I don't think it's at any risk of getting to sub zero, but no point taking a chance.

 

Will then leave it dry until we're ready to hook it up to the heating.