Who can solve this?

[armyash]

Hi guys

on call this weekend and this afternoon i got sent to a job, 2 issues at one property. First off the customer had snapped the handle off the stopcock in the house. Luckily i was able to replace the guts on it. problem solved.

2nd issue, the cold water tank is constantly filling through water running through the expansion pipe. Here's the thing, the customer has fitted a shower themselves, it's a thermostatic bar mixer type cheapy from B and Q.

DIal on water meter is spinning but no taps etc are on, no visible leaks. Both ball valves are working fine. When the water is coming through the expansion, if a hot tap is opened this stops. If the meter is turned off it stops.

At first i thought it was a split coil until he pointed out it stops if the mains are isolated.

All cold outlets are mains, all hot from the cylinder.

I'm thinking perhaps it's a faulty shower unit that is letting water through on the cold side and with no where to go it is sent through the shower unit and back through the hot and out the expansion.

What could this be?

 

[plumbdoctor]

I suppose the cold main through the shower could be back filling the cylinder and overflowing up and out the vent.

 

[armyash]

I suppose the cold main through the shower could be back filling the cylinder and overflowing up and out the vent.

it's the only thing i can think of. Shower was fitted on thursday they noticed the problem Friday.

 

[SimonG]

Mains cold, gravity hot, not a good combination. Chuck in a bit of diy and it all adds to the fun

On a sunday I would have cut and capped the hot and cold, charged them a fortune and said see you in a fortnight.

 

[Chalked]

They will have taken mains cold to mixer. Some mixers can cope with a pressure difference of up to 5 to 1.
But it will always mix better with a balanced pressure cold.
You have options.
1 connect the cold to the domestic tank.
2 fit a check valve to the shower hot supply.
3 Fit a pressure reducing vslve to the old supply
In reality there is only one option . Number one.

 

[armyash]

Mains cold, gravity hot, not a good combination. Chuck in a bit of diy and it all adds to the fun

On a sunday I would have cut and capped the hot and cold, charged them a fortune and said see you in a fortnight.

Couldn't even do that, it's insurance work, as the customer has done work on the system it's not covered. I was still there an hour investigating. I did sort his stopcock out but most guys would have walked off the minute they saw diy work. I'm too nice.

 

[armyash]

They will have taken mains cold to mixer. Some mixers can cope with a pressure difference of up to 5 to 1.
But it will always mix better with a balanced pressure cold.
You have options.
1 connect the cold to the domestic tank.
2 fit a check valve to the shower hot supply.
3 Fit a pressure reducing vslve to the old supply
In reality there is only one option . Number one.

You mean have the cold to shower mains fed? Yes that would be the best thing. Thanks.

The shower has non return valves built in so thought that might prevent things like this.

I said to the bloke take out the shower connections, repipe as it was and that will confirm it's the recent work that's the issue. He didn't like it, asked me to do it i said no. I said it wont be covered he said it will need to be proven that it was his work that's caused it. I said the chances of it being something else when you have done work are not very likely. In the end it got left with he will be getting a second visit to rule out the cylinder. No skin off my nose.

 

[Best]

Can really only be a mixer tap or shower mixer. If the only thing done has been a new shower mixer, then that's it. Often it just goes up the feed pipe of the cylinder and into the bottom of the cold water tank & overflows it.

 

[gassafe]

It's the shower, it's not a coincidence & his diy plumbing has caused it!

I'm guessing there's no dirty hot water, was the ch header tank even above the cold feed to cylinder...?

 

[wattsie1987]

Another vote for the shower had this exact same before.

 

[stevetheplumber]

some showers now mix before the on /of valve crazy idea to my mind

 

[Neil K]

I've got a problem in a block of flats at the moment where some clown has done a bit of diy, same thing. The cold water mains is mixing with our communal hw supply eventually overpowering it. Need to get into every single flat to find the culprit. Nightmare

 

[stevetheplumber]

how do you get paid for the call out flat fee or per call out

 

[jonnyswamp]

Write your report out stating that it's his own work at fault, making sure that it isn't covered under his insurance, teach him a lesson
It's *****oles like this who think plumbing is an overhyped trade and anybody can "fit pipes together or change a tap washer"
I also wouldn't have told him why/how it was back filling either, but let him know that I knew the reason

 

[Plumbstar Tom]

some showers now mix before the on /of valve crazy idea to my mind

Most do this now as the on/off control only needs to control 1 mixed feed and not 2 hot and cold feeds

 

[Plumbstar Tom]

I would just keep the report professional, that the shower valve was fitted incorrectly and caused the Cold water tank to back fill

 

[gassafe]

Did the customer fit this shower from new? Or was it a undo 2 nuts & replace type thing!? I guess he got unlucky if he only swopped the body & it started, but the shower was never installed correctly to begin with it seems!

Needs re-doing with a shower pump or fit unvented, or try the pressure reduce valve on cold to shower but not really a proper solution!

 

[armyash]

Not a swap, installed from new. He has tee'd in to the H and C at the bath taps and run plastic to the shower.

I'm actually really happy about this as I figured out what was happening (with confirmation on here as usual ) Proves to myself how much I have learnt.

I showed him the terms and conditions which state if work has been done on the system to cause the fault then it's not covered. He said it will have to be proven that it was his work, just to keep him happy i made a note on my job sheet that the 'customer requests second visit to rule out a split coil'. The bloke was a clown - plumbing and heating books laying around. When i said to him if you interfere with the plumbing it's not covered, he goes "what , so i can't even change a tap washer?" what's wrong with people? that's why he is paying the policy so he doesn't have to mess with it.

If my van breaks down it goes to the garage, i dont start messing with it.

I get paid so much a job on call out, if i only isolate it's one amount if it's an job that i can do there and then it's a little bit more. It was my first ever time on call out and i enjoyed it, the money isn't life changing but it's tops up my monthly wage if i get a few jobs. Call me mad but i enjoyed driving down the motorway at 3 am on one job with the stereo on smiling to myself thinking how happy i am to be in a decent job.

Thanks for all the replies.