Air in CH system and hot water returning to FE tank via the cold feed

[John.g]

Here is the info you are looking for. The PC 9706 on pump data plate (see pic of the pump) shows that it was in production in 1997.

Just received a photo of the pump, it seems a difficult one to track down, I presume the PC 0414 means it was manufactured in 2004.
Thanks again

 

[doitmyself]

I presume the PC 0414 means it was manufactured in 2004.

Week 14 of 2004 to be precise.

It's instructive to see how the performance of the 'same' pump has changed over time. (You should have three versions now.)

 

[Ajlsat]

sure i am in wrong place, can someone direct me. where to ask question ref heat pump instalation.thanks

QUOTE="John.g, post: 1022186, member: 99812"]I suppose we should bear in mind that the UPS2 hasn't true fixed speed curves. Even speed 1 will give a constant head of 4M from 0 to ~ 6 LPM before the head starts falling, (any real fixed speed pump head starts dropping immediately on flow demand) which with modern zoning/TRV's etc will cater for over 6 kw of heat demand at a deltaT of 15C. and with the retro fitting of condensing oil/gas boilers the trend is to get a greater deltaT of 20C to enhance the condensing effect thus leading to even lower circulation rates. So in a house with even just basic insulation could very easily be running the UPS2 pump at the ridiculously high head of 4M on "fixed speed" for significant periods of time.
I havn't any pump curves for the older UPS pumps but I would think that they would have been operating at least 1/1.5M lower head?
Having said that the 3M PP head is a bit mean to say the least and certainly will fall short in a lot of instances as on PP control the head falls with reduced flow demand so to cater for both full heating flow rates and reduced demand it would have been nice if 3.5M to 4M was available, as was pointed out above, The UPS 3 has now got a 3.6M PP head. (AND has two CP (constant pressure) settings as well!)
This one may have been replaced in a lot of cases by the UPS 2.
https://product-selection.grundfos....tid=GMA&productnumber=97549426&qcid=501056454[/QUOTE]

 

[SJB060685]

So if your ballcock were not refilling the F&E, and no overflowing took place, you think the volume of water in the system would stay the same? There isn't any being added, by, say, a leak from the coil in your hot water cylinder?

Took the words out of my mouth lol

 

[John.g]

Took the words out of my mouth lol

The air in the rads is/was displacing the water??

 

[SJB060685]

The air in the rads is/was displacing the water??

Well any air in the system will displace water. I thought my post was agreeing with someone suggest a split in cylinder coil?

 

[John.g]

Well any air in the system will displace water. I thought my post was agreeing with someone suggest a split in cylinder coil?

I thought the OP ruled that out by changing the pump settings to PP control which reduced the pump head and stopped the water returning to the feed & expansion tank and drawing air in through the vent. If the coil is split he would be getting a continuous overflow from the F & E Tank.

 

[SJB060685]

I thought the OP ruled that out by changing the pump settings to PP control which reduced the pump head and stopped the water returning to the feed & expansion tank and drawing air in through the vent. If the coil is split he would be getting a continuous overflow from the F & E Tank.

Yeah but I thought I said that before I’d read every comment lol. I know you suggesting or whoever it was to make this adjustment solved it.