Reconnecting my G/F Radiators using an UFH Manifold

27 Nov 2023
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United Kingdom
Won't go into the reasons and much is personal preference but after a full basement dig out which meant all my G/F radiator pipework had to be ripped out, I have decided to reconnect them using an UFH manifold, with one loop for each room. Had enough Pex-Al HDPE pipe for 2 rooms but have one still to go and have 2 questions:
1. To connect the 16mmx2mm pipe to the copper going up through floor, i was looking at the Eurocone connectors. But the insert seems really to narrow the pipe and am wondering if there are other types that narrow it less. I'm thinking of friction and flow restriction around each circuit. (although I know I have these on the manifold but surely 2 restrictions in a loop is better than 4 (Including flow and return). Or does it not really make much difference. (Also, as I will need more pipe I could just use 15mm Pex instead. Is there an advantage doing this or would I be better to add just a bit more 16mm Pex-Al-HDPE. I have half of what I need already.)

2. The final room has 2 radiators and I'm wondering if it is worth connecting them in parallel or if a series loop would be easier - well it will be for me and will need less pipe. There are so many posts about Parallel vs Series but they all seem to apply to an entire circuit. I'm just looking at the rads in one room being connected this way. Options are to have 2 circuits off the manifold, one for each rad or one circuit with rads in series. I'd prefer the latter unless the experts out there give a reason not to. I know the second rad will run cooler but maybe that also means the first one will run hotter and so the net will be the same. I have also read about pump loads and pressure etc but the analysis out there seems to indicate this will make little difference - especially as it will only be 2 rads in one room and coming off a manifold.
When all done, will be controlled via Actuators on the Manifold and a Room Thermostat

Thanks in advance for any advice..
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Just use std brass manifolds and feed - return each rad as required from the manifold via the boiler feed?

Series is a terrible idea for radiant heating. You may as well not bother for the agro.
I already have the manifold with 2 loops installed and working well. so not sure what you mean by standard brass manifolds. Mine are ufh ones with shutoff valves, temp gauges and pressure gauge. Also flow control on each circuit and will add actuators.
so question is which connector is best for copper to 15mm or 16mm Pex pipe.
you really think series for 2 rads in a single room - second rad quire small is not worth doing and I should pipe both to separate manifold ports. Will need double the pipe and 2 actuators and more connectors. Just trying to justify this.
15mm x 16mm pex compression elbows are available just do a search!
What's the output of the 2 extra rads and distance from manifold?
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Rads are:
Sitting RoomBigP+
Sitting RoomSmallK1

First rad is 4m from manifold and second is 4m from there (taking into account pipe routing)
Need straight connectors. I know I can get them its just that non really show pictures. I know the eurocones work but with compression joints you also need to get the appropriate insert and I'm wondering if that also reduces the diameter as much as eurocones. No websites ever show detailed pics except the ones with eurocones so I can't really see. And then have to get insert too. Would really help to kn ow a brand or stype by name that works
I'm going to connect them first in series and use one manifold port pair and try it out. If it doesn't work well, then I'll separate the loops. It's not really any wasted work as only need to remove the connection between the rads before adding in the two extra lengths. It would be easier in series as save on pipe and connectors and, when the time comes, an actuator and a slot on the controller unit.. But will know pretty soon after connection if the series method doesn't work well enough and very easy to modify.

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