My Install - some questions!

[Duncan62]

Hello all, thanks to the fantastic BH I've had a go at my UFH / DHW install. 

 

Be nice (please!) but tell me if it's wrong!

 

Q1: how do I go about filling the system? Do I use the full and flush valve, hose pipe? Or pipe in a hep2o from mains?

 

Q2: I have a huge plastic container of glycol for anti freeze. How do I get that in the pipes? How do I get the correct ratio?

 

Observations:

DHW Will loop to UVC, but currently loops back to exit so I can get the system running as I need to commission the slab with heat cycle.

[Nickfromwales]

31 minutes ago, Duncan62 said:

Hello all, thanks to the fantastic BH I've had a go at my UFH / DHW install. 

 

Be nice (please!) but tell me if it's wrong!

 

Q1: how do I go about filling the system? Do I use the full and flush valve, hose pipe? Or pipe in a hep2o from mains?

 

Q2: I have a huge plastic container of glycol for anti freeze. How do I get that in the pipes? How do I get the correct ratio?

 

Observations:

DHW Will loop to UVC, but currently loops back to exit so I can get the system running as I need to commission the slab with heat cycle.

Nice work. 
 

You need to tee into the hard cold mains feed and connect this part of the “filling loop”.   

 

 

Don’t use softened water.

 

That filling loop is how you fill the heating system. 
 

Fill and test for leaks without treating it, check for the next 48/72 hrs to be certain you’re kosher, and only then do you put the glycol in. 

[JohnMo]

30 minutes ago, Duncan62 said:

freeze. How do I get that in the pipes? How do I get the correct ratio

Best ratio - is no glycol at all - why are you adding. It just degrades system performance. If you really want freeze protection for warranty, buy two anti freeze valves. But ones that respond to water temperatures not outside temperature.

 

The flexible hose by the expansion vessel, should tee into the cold water main and act as filling loop.

 

But you UFH loops will need filling and air got out of the system - you would use a hose on the UFH manifold for that, one loop at a time.

 

Not seeing many useful auto bleed points

[Nickfromwales]

These 2 are supposed to be the other way around, so you can clean / service / replace the double check valve by turning the stopcock off. 
 

Should be a quick swap with just a spanner. 
 

[Nickfromwales]

3 minutes ago, JohnMo said:

Best ratio - is no glycol at all

Not if the ASHP manufacturer states that it is mandatory, in the MI’s. 

 

Bottle vent on the manifold seems to be suffice, as it looks to be the highest point there. 
 

The feeds to upstairs should vent through the heating up there, vent on manifold #2 or rads. 

[JohnMo]

3 minutes ago, Nickfromwales said:

Not if the ASHP manufacturer states that it is mandatory, in the MI’s. 

True, but do any modern ASHPs say glycol is the only option?

[Nickfromwales]

Just now, JohnMo said:

True, but do any modern ASHPs say glycol is the only option?

Whether we like it, or dislike it, agree or disagree, the manufacturers installation guide is the bible. 

 

Some dont stipulate, some do, some are happy with anti-freeze valves, which I opted for on the last ones where I had 'free reign', but we should make the OP aware that they need to check if they are OK to deviate.

 

Me personally, I hate the thought of glycol. No need for it, but there is always the power cut in the arse of winter to consider as worst-case.

[Duncan62]

9 hours ago, JohnMo said:

 

Not seeing many useful auto bleed points

 

There is just 1 currently, as nick pointed out, on the UFH manifold.

 

The pipes running upstairs are for a FCU and there is no bleed on them. Shall I add one up there?

[Duncan62]

8 hours ago, Nickfromwales said:

 

Me personally, I hate the thought of glycol. No need for it, but there is always the power cut in the arse of winter to consider as worst-case.

 

Thanks guys. 

I shall check the manufacturers booklet again. 

 

Perhaps the actual flow temp anti freeze valve is best... I certainly don't want to compromise on CoP!

[Duncan62]

Q3:

 

How much"flushing" of the system is required?

I've put it together and been very careful along the way.

Happy to flush, presume that's what the fill flush valve is for, so I can have the dirty water exit before the HP.

 

Just want to know how critical this step is.

[Nickfromwales]

9 minutes ago, Duncan62 said:

The pipes running upstairs are for a FCU and there is no bleed on them. Shall I add one up there?

Double check that   Of there’s definitely not one, then yes it’ll need an auto air vent. 

 

7 minutes ago, Duncan62 said:

 

Thanks guys. 

I shall check the manufacturers booklet again. 

 

Perhaps the actual flow temp anti freeze valve is best... I certainly don't want to compromise on CoP!

Do as the good book says, because if you deviate you’ll be without warranty. Don’t ring their tech support to ask verbally, if you decide you’d like to explore this intensively, and ask them by email; if they say to use glycol in the book but say you can omit it, you’ll need that in writing. 

 

4 minutes ago, Duncan62 said:

Q3:

 

How much"flushing" of the system is required?

I've put it together and been very careful along the way.

Happy to flush, presume that's what the fill flush valve is for, so I can have the dirty water exit before the HP.

 

Just want to know how critical this step is.

Do you have a particulate filter in the line? Usually a large 1/4 turn isolator with a big hex nut that you undo, with a small stainless steel gauze filter inside. 

[Duncan62]

23 minutes ago, Nickfromwales said:

 

Do you have a particulate filter in the line? Usually a large 1/4 turn isolator with a big hex nut that you undo, with a small stainless steel gauze filter inside. 

 

I have the filter on the outflow, an Intaklean unit.

 

Nothing anywhere else.

[JohnMo]

40 minutes ago, Duncan62 said:

 

I have the filter on the outflow, an Intaklean unit.

 

Nothing anywhere else.

Again check your install instructions - mine explicitly stated a strainer must be installed and you’ve provided one. It also says if you have magnetic filter they also had to be installed 

[JohnMo]

1 hour ago, Duncan62 said:

How much"flushing" of the system is required?

If it's all new nothing much, enough to get air out. Circulation pump on for an hour, cleaner filter and strainer 

[Nickfromwales]

42 minutes ago, Duncan62 said:

an Intaklean unit.

Is it heat pump specific? You need a particle filter as well as a magnetic filter to catch all types of debris.