Old Domestic Hot Water Pipework & New Combi

[DesperateStan]

I am about to have a new combi & radiators fitted in a system with pretty old CH and HW pipework. Is normal practice just to replace the CH pipes? If so is it usual for the HW pipes to leak when they get pressure tested having led an easy life for years just being gravity fed.

Or should a new pressurised system have new pipes throughout?

 

[corgiman]

According to water regs ALL water fittings should be able to with stand a test of 1.5 times the expected standing pressure

Before you either whack the combi on what you have got or rip it all out get your plumber to carry out a test to see if they can withstand it

I think (and i cannot find my reg book at the mo so I am not sure) the test should be for 20min but am sure the lads will put you right if I am wrong

 

[ChrisR]

You might consider new rad valves all round, they're quite likely to weep.
Not many old pipes leak, but it can happen, sometimes only when they get hot

 

[DesperateStan]

Thanks to corgiman and Chris R for your replies - our water company tells me they guarantee 1 bar at the stop cock; expect 1.5 bar in the main and design new for 2 bars. These pipes are 75 yrs old but if the cold can take it I guess the hot should too. I'll see how they cope with the pressure test (tomorrow) & hope for the best.