Builder wants to install an automatic filling valve

eggerb

I'm coming towards the end of an extension build and the builder has just put in a 2000m x 600mm rad which doesn't seem to be heating up properly. The builder says it is because the rad is at the end of the loop and the pressure on the system is very low.

He wants to add an automatic filling valve and pressure the system off the mains water supply.

Does this sound like a good or bad idea? Are there any other options or additional measures I should insist on?

items

You have a circulation problem, adding pressure doesn't really improve circulation, not in that way as you mention above. 1st thing to do is balance heating to gain some more circulation power. You could close off returns on rads that heat up quick a little more 1/4 / 1/2" turn, also look at your cylinder coil, the balance valve should only be around two turns open from closed, if its any more closing it down some might help. Check pump setting, might be able to increase pump power.

If all else fails go for bigger head circulation pump, you might have a 5mtr head, go up to 6mtr. If you have a pump built in (system gas boiler) you could add an additional pump to heating system, on return pipe work (opposite of existing pump).

Connecting mains permanently via PRV is not a good idea, most regulation goes against it for obvious reasons (contamination) but as usual Ireland is a bit behind, if connecting heating to mains use a dedicated mains filling loop, heating can be filled from mains then disconnected when required pressure is reached, all with out use of tools.

Joey the lips

No its not a good idea. In my opinion an automatic filling valve shoud be outlawed and made illegal. Tell the builder you want a combi filling loop and you want it disconnected from the main as is correct procedure when the system is filled and the correct pressure is reached.

As items says this has noting to do with why your rad is not heating. In fact without knowing the builder I already have a bad impression of him as this is a method of hiding pressure leaks and pressure leaks are usually water leaks. This also leads to the introduction of contamination in the system with accelerates the breakdown of your radiatiors.

A combi filling loop is usually fitted in the hot press where the mains is coming into the heating system. This is a picture of one.




and just so your clear this is a picture below of an automatic filling valve.

http://pulsar.ie/plumbing-supplies/productdetail.asp?ProductCatId=134&ProductSubId=5&ProductCode=COMB05

I have attached a link as the picture is quite small but the difference is quite to see. The auto filling valve has a gage and big turning head where as the combi filling loop whis braided hose. Generally speaking

eggerb

Thanks very much for the replies Joey and items. I left work early at lunchtime to go home and tell him I wanted a combi filling loop but it was too late; he had already fitted the automatic filling valve.

It seems that there was a pipe being feed from the hot water storage tank (gravity feed) in the attic that he connected up to the mains and put a automatic filling valve in the middle.

Between/above the supply and the valve there is a valve I can turn so it looks like I can close that so that it not permanently connected to the mains.

After/below the valve, there is anti pass-back (or whatever it is termed) so that there is no (??) danger of contaminating the mains.

I totally understand the argument about automatically filling the system (not seeing leaks etc) so, my plan would be to turn off the supply from the attic and make a choice each time to fill the system.

I understand the argument about connecting it to the mains for contamination risks etc but hope the back-pass valve removes that risk.

However, those two considerations aside, I'm not exactly sure what the combi filling loop does better than the AFV used in the manner I am proposing. For a total novice like me, it even gives me a guage to see what my pressure is at. Just thinking of the gauge, I'm not exactly sure how that can work if the anti back-pass is below it.

Thanks again for the replies and sorry for the incorrect terminology!

Joey the lips

Its all up to you

Micky Dolenz

The auto filling valve will have a non return built in. Leave it in, just turn it off and only turn on when filling system.

I agree with the lads, they are offensive and should be banned (they are in the UK)

Micky Dolenz

Oh, on the rad front. They may have tapped into a 1/2" supply. This could mean that a few rads of off the supply and this rad is being starved of cirulation. As Items suggested, upgrading pump may work. ths system will need to be balanced either way.

eggerb

Thanks for the input everybody. I suspect he may have tapped into a small pipe alright. He's not back until next week so I am going to see how I get on over the next week or so. I'll give balancing a go and see if this helps also.

The problem I am encountered my explain his unwillingness to incease the size of a another rad in a room I have problems keeping warm.

Thanks again.

items

Rule of thumb, never take more than two rads off 1/2" pipe any more than two will lead to rads which lack output. Factory's base their rad outputs from good flow rates, 1/2" pipe feeding more than two rads gives bad flow rate.

When circulation problem is sorted, if rad is just as hot as others but you find rooms not heating up then rad is undersized. Most handy men / builders etc seem to come up with rad sizes off the top of their head or simply areas where rad might fit, thats not the way to fit rads.

A heat loss calculation / heat requirement of room has to be made up with rad output matching calculated figures.

Rooms with more than one external wall tend to be harder to heat, a lot of undersized problems happen in those type of rooms.