No. The 22mm flow and return pipes do not connect to each other.
In the diagram above, if the flow comes in from the left, the 22mm flow pipe runs the full length from the first to the last radiator, and is connected to one side of each radiator by a 15mm pipe.
A separate 22mm pipe for return comes in from the right hand side, and runs the full length from the last radiator to the first one. This return pipe is connected to each radiator on the opposite side from the flow, again by 15mm pipes.
The water therefore flows from the flow pipe, through each radiator, and out to the return pipe.
Addenda: The heat pump is currently heating the water and the pipes both sides of the ABV are hot.
As Ian has stated, it is difficult to check if an ABV is passing or not, since without accurate pressure measurements, temperature alone may not be adequate. It may also depend upon where in the system the ABV is located.
Since 1 bar is equivalent to a head of water of approximately 32 feet, then the present setting of the ABV at 0.3 bar is approximately 9.6 feet, so if the highest point in your system is greater than 9.6 feet above the ABV, there is the possibility that the ABV may be opening.
I would suggest increasing the setting of the ABV from 0.3 bar to 0.5 bar which is equivalent to a water head of 16 feet, then see if that makes any difference to the way that your system operates.
1. Is the highest point the top of the highest radiator?
2. How do I change the setting on the ABV?
Thanks again.
As Ian has stated, it is difficult to check if an ABV is passing or not, since without accurate pressure measurements, temperature alone may not be adequate. It may also depend upon where in the system the ABV is located.
Since 1 bar is equivalent to a head of water of approximately 32 feet, then the present setting of the ABV at 0.3 bar is approximately 9.6 feet, so if the highest point in your system is greater than 9.6 feet above the ABV, there is the possibility that the ABV may be opening.
I would suggest increasing the setting of the ABV from 0.3 bar to 0.5 bar which is equivalent to a water head of 16 feet, then see if that makes any difference to the way that your system operates.
@riponowl just set it to 0.6, the highest value. you don't need to "tune" it, you are not trying to balance a TRV boiler system which is what they were designed for, you want it set as close to closed as it can be without being able to change the plumbing so that its not there.
It is the highest point in the pipework through which water will be required to flow, since the pump has to push the water uphill against gravity.
As far as adjustment is concerned, it is probably just a matter of turning the black plastic ring until the red indicator is at the required setting. If that is not correct then note the name of the manufacturer and use Google to find a manual.
Having said that your other limiting factor may be the capacity of your 7 radiators. Can you indicate the DT50 rating of your radiators? Or size and model ref
This was supplied by the installer, I hope it is of use. I think all the new radiators are by Ultraheat. I've looked up the BTUs and added that at the side.
Having said that your other limiting factor may be the capacity of your 7 radiators. Can you indicate the DT50 rating of your radiators? Or size and model ref
This was supplied by the installer, I hope it is of use. I think all the new radiators are by Ultraheat. I've looked up the BTUs and added that at the side.
So the total output capacity of your radiators at the standard DT 50 is 17kW. It will be interesting to see how this compares with your heat loss calculation, since the actual output of the radiators even at a LWT of 50C will be considerably lower than 17kW, probably in the region of 7.45kW.
At a LWT of 40C, the thermal energy supplied will only be 4kW.
Having said that your other limiting factor may be the capacity of your 7 radiators. Can you indicate the DT50 rating of your radiators? Or size and model ref
This was supplied by the installer, I hope it is of use. I think all the new radiators are by Ultraheat. I've looked up the BTUs and added that at the side.
-- Attachment is not available --
So the total output capacity of your radiators at the standard DT 50 is 17kW. It will be interesting to see how this compares with your heat loss calculation, since the actual output of the radiators even at a LWT of 50C will be considerably lower than 17kW, probably in the region of 7.45kW.
At a LWT of 40C, the thermal energy supplied will only be 4kW.
hi @derek-m I’ve been looking at your post and recognise what you’re saying and worked out the emitter output for all 7 rads at LWT 50.
Can you confirm if im missing something
based on 17.07 kWh : LWT of 50c and a Temp drop of 5C across the rads: I’m getting 12.65KWh
KWh = 50-20-2.5= T27.5 X 0.46= 12.65
ive chosen 0.46 as the mid point between .51 and .41 (correction factors for T30 and T25)
any observations appreciated.
@riponowl the above is a calc to clarify what output your rads would put out when operating with leaving water temperature of 50c. (If I’ve done the maths correctly)
I’ve also done a calc for a LWT of 40c which comes in at 4.55 kWh.
I used the spreadsheet calculator that I developed some time ago, a copy of which I have attached. I think that you should be multiplying 17kW by 0.46, which would give you an answer of 7.82kW at an IAT of 20C. I used an IAT of 21C, hence the 7.447W figure.
The cells highlighted in yellow can be changed, with the answer being provided in cells A6, B6 and C6. Please ignore the larger table below.
