Piping disagreement with builder

chuck eastwood

So im adding a small wash room onto the back of the house with two small rads. I have a pumped zone circuit with one small rad left fully open all the time with no trv on it to prevent over pressuring the zone.
My problem is the builder thinks the new rad should have a pipe linking the flow and return before entering the last rad. No im a pipe fitter by trade and not a plumber, im also open to being told im wrong. The attached drawing is a sample layout from systemlink . Ie . The blue line at the end of the loop is what the builder wants to do. I think it will decrease the flow through the rads as it is an easier route than going througj the rads. The system functioned perfectly well when piped without a loop like the blue line for 5 years. So eh, who is right. Me or the builder

EdgeCase

If you turn off that radiator it'll close the whole loop and leave the pump pumping against a closed closed circuit.

Effectively, you've one radiator connected in series instead of in parallel for no real reason. It will work but only if that radiator is always left open which isn't giving you any control.

You shouldn't have any issue with overpressuring of the zone. Is there an appropriately sized pressure vessel on the system? An open radiator won't reduce or regulate system pressure.

Is also essential that whatever way your zoning valves are setup, the pressure vessel always remains connected to the loop.

chuck eastwood

EdgeCase wrote: »

If you turn off that radiator it'll close the whole loop and leave the pump pumping against a closed closed circuit.

Effectively, you've one radiator connected in series instead of in parallel for no real reason. It will work but only if that radiator is always left open which isn't giving you any control.

You shouldn't have any issue with overpressuring of the zone. Is there an appropriately sized pressure vessel on the system? An open radiator won't reduce or regulate system pressure.

Is also essential that whatever way your zoning valves are setup, the pressure vessel always remains connected to the loop.

Its a gravity fed system. No pressure vessel needed in this case. My main argument with him was him adding in the pipe (blue line) would allow a path of least resistance taking flow away from the rads. Told him to change it anyway

Your right, you only need a bypass rad to allow constant movement when all the other rads shut down saving your pump from living a short life.

chuck eastwood

gary71 wrote: »

Your right, you only need a bypass rad to allow constant movement when all the other rads shut down saving your pump from living a short life.

Yeah thats what i have on each zone. Thanks

Tom44

Am I the only one with brains here ?

https://www.ie.screwfix.com/straight-auto-bypass-valve-22mm.html?utm_source=Google&utm_medium=CPC&utm_campaign=Shopping&gclid=EAIaIQobChMI3KDFxsHO2gIVCBIbCh1CyQRwEAQYAiABEgIqN_D_BwE&gclsrc=aw.ds

chuck eastwood

Tom44 wrote: »

Am I the only one with brains here ?

https://www.ie.screwfix.com/straight-auto-bypass-valve-22mm.html?utm_source=Google&utm_medium=CPC&utm_campaign=Shopping&gclid=EAIaIQobChMI3KDFxsHO2gIVCBIbCh1CyQRwEAQYAiABEgIqN_D_BwE&gclsrc=aw.ds

Brains no, attitude maybe. That pressures relief/bypass isnt necessary if one rad on each zone is kept open and no TRV fitted. Thanks for your input all the same

gctest50

chuck eastwood wrote: »

Brains no, attitude maybe. That pressures relief/bypass isnt necessary if one rad on each zone is kept open and no TRV fitted. Thanks for your input all the same

Or instead of some wonky house-of-cards crap setup with no trv on one rad and a terms and conditions poster beside it detailing why it shouldn't be turned off because deadheading the pump may shorten its operating life

- just put in the bypass valve in case someone doesn't read the notice

- but that would involve going back to the builder and asking him to put in the "blue" pipe with a bypass on it ( or similar )


TLDR : you didn't get the answer you wanted and will now have to go crawling back to the builder like a craven cur

Outkast_IRE

Nothing wrong with having one rad on the circuit with no trv. This would not be considered an unusual setup in domestic situations . I would say think about putting a lockshield head on the valve so it can't accidently be closed.

The manual bypass can be fitted anywhere on the circuit so near the system link is probably easiest if you wanna go that route.

My recommendation to you is to fit the auto bypass near the system link and put a trv on the rad that currently doesn't have one . It would be considered an improvement on your current setup.

chuck eastwood

gctest50 wrote: »

Or instead of some wonky house-of-cards crap setup with no trv on one rad and a terms and conditions poster beside it detailing why it shouldn't be turned off because deadheading the pump may shorten its operating life

- just put in the bypass valve in case someone doesn't read the notice

- but that would involve going back to the builder and asking him to put in the "blue" pipe with a bypass on it ( or similar )


TLDR : you didn't get the answer you wanted and will now have to go crawling back to the builder like a craven cur

Its an easy job to fit that bypass valve in the press. Its certainly not a bad idea to have it on each zone but it would make more sense to fit it where it can be got at and not hidden behind the plasterboard. The suggestion from the brains was a good one and one i will fit myself. That said the original question was what purpose would that link pipe serve other than creating a bypass for the water instead of going through any rads under reasonable pressure

chuck eastwood

Outkast_IRE wrote: »

Nothing wrong with having one rad on the circuit with no trv. This would not be considered an unusual setup in domestic situations . I would say think about putting a lockshield head on the valve so it can't accidently be closed.

The manual bypass can be fitted anywhere on the circuit so near the system link is probably easiest if you wanna go that route.

My recommendation to you is to fit the auto bypass near the system link and put a trv on the rad that currently doesn't have one . It would be considered an improvement on your current setup.

Yeah i have lock shields on the rad on each zone that i have opened so they cant be accidentally closed. I have literally just placed an order for two bypass valves. Better safe than sorry as ive upgraded the pumps two months ago. For the sake of €20 i might as well fit the valves. Thanks for your reply

Rad circuits with trvs have always required a balancing rad(usually bathroom) to prevent noise issues and undue stress on the pump this was the thinking before system link was invented and added a different approach where you can now find circuits without a obvious bypass rad(no bathroom) auto bypass valve would be a good option if the homeowner wished to control all the rads.

Personally I prefer a bypass rad for its simplicity as I check a lot of auto bypasses when I’m in homes and most are not working correctly which wouldn’t be obvious to a home owner compared to a bypass rad which is easy to determine it’s performance.