Advice for one-pipe system

[marc1977]

Hi,

I recently moved into a house that has a one pipe system. It all works absolutely fine however when I replaced one of the old radiators it isn't as fast and hot as before. The plumbing is the same except I used pushfit connections so perhaps they have a smaller bore or perhaps new rads dont allow the water to flow as the older ones???

Anyway my dilemma now is to either pay to have it replaced with a 2 way system or try and get it working. I've had 4 plumbers round:

1) one is a very good polish building firm I've used before who quoted £3.5k for a complete refit
2) One is an ex British Gas guy who quoted £4k for a complete refit
3) 2 plumbers said not to bother with a refit and quoted £1500 to replace all 9 rads, balance and flush the system out.

One thing that puts me off a refit is we have a solid wood floor downstairs so all downstairs pipework would have o be chased into walls - lots of mess and re plastering needed! However we are planing to decorate whole house eventually so not a major issue.

Any advice much appreciated.

 

[Gasmk1]

did you replace the valve for a thermostatic radiator valve if so it may be wrong type as you need a full bore trv on one pipe systems

 

[ShaunCorbs]

The key is are they gas safe registered bet you 2 out of the 4 arnt

If it was me new Pipework and rads and depending on boiler age / condition change that as well you will be set then no problems if installed right

 

[Chalked]

Bin the last one! Balancing a one pipe is a last resort. If you can afford it, get it re-piped. Much more efficient and a quicker heat up.

 

[marc1977]

Cheers, boiler is only 2 years old so that's fine. I did use TRV's but the old radiator also had standard TRV on it and worked ok! I hate one pipe systems!

 

[Gasmk1]

are you sure it was standar a standard trv only has a flow hole of about 5mm diameter whereas a full flow one is about 10mm dia

 

[marc1977]

yes, ive even tried removing the TRV but it doesn't help. Its annoying as the radiator does work, its just at 80% rather than 100%. Given i plan to live in the house for the next 50 years I may as well bite the bullet and get it redone.

 

[Scott_D]

You took the trv off or the trv head off?

 

[marc1977]

The TRV! Im not that much of a numpty!

 

[SimonG]

Plastic out copper in. Have a look at the internal diameter of a 15mm insert.

 

[AWheating]

rad valves need to be full bore, some trv only have a 6mm hole in them.