Drop in water mains pressure

[JoeJoe]

Had to have the old (combi) boiler replaced. New boiler required an upgrade to the gas supply, so decided to have it installed at the opposite side of the house (in the garage) as upgrading the old gas pipe would have involved damaging tiled flooring.

The pipes where the old boiler used to be were capped, and the new (combi) boiler installed, and everything is working again (hot water + heating).

Only problem is that the cold water mains pressure seems to be much lower than it was prior... That is the case throughout the house (most noticeable in 3 bathrooms with sinks + kitchen sink).

The plumber simply capped the mains that went to the old boiler and branched from the pipe feeding the downstairs bathroom to the new boiler. I am certain that he hasn't touched the stop c*ck (or whatever it is called) in the driveway (there is a valve that could be closed before the new branch).

Before I speak to the neighbour tomorrow morning to see if they experienced something similar, is there anything that could have caused this? I've lived in this house for 7.5 years, and the pressure has always been the same, so it seems like a bit too much of a coincidence...

[harry]

He must have shut the water off somehow to do the work. I would start there. If the valve he shut off was old, it may have been damaged (by the act of closing and opening it) and not opened properly. (See recent thread about dezincifying.)

Also possible some crap in the pipework has been dislodged and jammed up somewhere else reducing flow.

[JoeJoe]

The mains pipe enter the house, and then branches to various parts of the house (upstairs, etc). The first of the branches goes to an electric shower downstairs. No stock c*ck for the whole house, but there is one before the shower. He connected the new boiler to that branch - AFTER the stop c*ck (asked me if it was OK with me), so that 1. he didn't have to use the stop c*ck in the street; and 2. to give the option to isolate the boiler (and the shower...) should it need to be isolated.

I also thought about damage to that stop c*ck for the shower. However, the low pressure is throughout the house, and the feed for that are from branches off the mains feed further down the line, so shouldn't really be affected I would have thought?

That may be the answer. I think it may be my turn to crawl under the house later today... ;-(

>

[Brian Gaff]

Silly question, but are you sure he took the feed from the correct place?

Brian

[JoeJoe]

Just been under the house with the heating guy/plumber who is very experienced and sensible (and as confused as I am)...

22mm feed from the street running under the house, then going upstairs (still in 22mm) where it supplies 2 bathrooms (2 sinks, 1x electric shower, 1 shower off the combi). All were fine until 2 days ago, now pressure is low for all of them.

Downstairs: just before it goes upstairs the 22mm is reduced to 15mm. From there it is branched for an electric shower (from where the boiler is now also supplied), and continue in 15mm to the kitchen + utility room sinks (both were fine, now low pressure), and to the old boiler (now capped).

He could only think of a possible blockage in the mains before it goes upstairs (perhaps when it is reduced 22mm-20-15mm), and suggested that when he comes back to fit a couple of new radiators he would uncap where the boiler used to be and try and flash it?

Does it make sense? Any other suggestions?

[Phil L]

Have you been in touch with your water supplier? - they may have had a burst main somewhere or are doing other work nearby and could have re-routed your water main to a different supply temporarily

[JoeJoe]

Sorry, forgot to mention that I phoned them first thing this morning, and there was nothing reported for our address/street.

Also, spoke to our next door neighbour - everything as it has always been...

[robert]

You havent got a leak somewhere have you ? Can you measure the static water pressure ( no flow) maybe on the new boiler will give you some idea if there is a problem with the feed to the house. You could then see how much it drops when you have flow and decide whether this is excessive which would indicate an obstruction.

[JoeJoe]

Don't think so. Certainly not upstairs as I would have noticed it by now. Also crawled under ground floor and couldn't see anything. Only a small area is inaccessible, but should have noticed something by now.

That's the plan when the plumber comes back in a couple of weeks. Thanks again.

[geoff]

In message , JoeJoe writes

A house near me suffered a drop in mains pressure

It's OK - they found the leak ...

[GMM]

Wow - and I thought I had a few cracks in my house!