Yep, it's looking that way. Would I be right to assume a universal would do the job the same as a negative head? Only issue with those, apart from being about twice the price is that they tend to be taller and so might not fit under the bath.
Pumped shower now won't supply hot under any circumstances
- Thread starter joefuller
- Start date
It shouldn't be under the bath!
Andy
Andy
A universal pump is the new(ish) name for a negative head pump.
Have to agree, a pump really shouldn't be under the bath, especially if it's near the max of 4M effective pipe length form the HW cylinder. It all slows the flow down through to the shower, which is what seems to be happening here. (Edit) Ideally It should be sited in the same space and at the bottom of the cylinder.
There shouldn't be any need to, pumps work fine when installed correctly. The trouble here seems to be the install(er), I'm afraid to say.
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As above, a negative head pump is required which the installers should have known, get them to install that and just pay them the difference in the cost of the negative head pump and the presently installed positive head pump.
It's 2m absolute tops at the moment.
The other major problem with pumps is unbalanced supplies, it never really works properly without fudging it with limiting the supply or using pressure reducing valves. Looking @ the installation instructions for most, if not all pumps, no where does it prescribe just pumping the hot side and running the other side from the mains, it just leads to problems, if not with the pump then temp control @ the shower. I can also screw up any manufacturers warranty.
Again the installer should know this though, if they don't then TBH they shouldn't really be doing the job.
Again the installer should know this though, if they don't then TBH they shouldn't really be doing the job.
Another update and potential solution!
It looks like the problem could be something nobody thought of! They came back yesterday with a different shower tap unit to test a theory about pressures. This one only has a handset outlet, not one with a rain head as well like the existing one that doesn't work, but not sure that's relevant to the failure identified. They put this one on and it immediately worked. The pump instantly kicks in (that's the positive head one, under the bath) and does everything expected. They said that on inspecting the original unit, it was blocked with debris. That would explain both why it doesn't work and also why it kept re-failing whenever a 'fix' was found. They took it away last night to clear the debris and refitted it today and it still doesn't work so it looks like that original unit is broken beyond just being blocked. For now, the 'spare' unit is installed with just the handset but seems to be working fine.
It looks like the problem could be something nobody thought of! They came back yesterday with a different shower tap unit to test a theory about pressures. This one only has a handset outlet, not one with a rain head as well like the existing one that doesn't work, but not sure that's relevant to the failure identified. They put this one on and it immediately worked. The pump instantly kicks in (that's the positive head one, under the bath) and does everything expected. They said that on inspecting the original unit, it was blocked with debris. That would explain both why it doesn't work and also why it kept re-failing whenever a 'fix' was found. They took it away last night to clear the debris and refitted it today and it still doesn't work so it looks like that original unit is broken beyond just being blocked. For now, the 'spare' unit is installed with just the handset but seems to be working fine.
A further update!
Yesterday afternoon, after the spare unit was fitted, the overflow pipe from the loft started flowing and on inspection the header tank was overfull. I thought the water was slightly warm but put that down to it being roasting in the loft. The flow stopped after having a shower, until it got full again. The guy came back and adjusted the ballcock. It started overflowing again. I looked last night and could see nothing coming from the ballcock valve and wondered if it could be coming back through the pipe that supplies the HW cylinder but assumed there would be something to prevent this. Now it has started overflowing again today and he has come back and confirmed that it is indeed coming back up from the HW tank into the header tanks because of a failed NRV inside the spare shower unit.
This is never ending!
We will be fitting a new one of the original shower tap with the handset and rain head and hopefully that will be then end of this!
Yesterday afternoon, after the spare unit was fitted, the overflow pipe from the loft started flowing and on inspection the header tank was overfull. I thought the water was slightly warm but put that down to it being roasting in the loft. The flow stopped after having a shower, until it got full again. The guy came back and adjusted the ballcock. It started overflowing again. I looked last night and could see nothing coming from the ballcock valve and wondered if it could be coming back through the pipe that supplies the HW cylinder but assumed there would be something to prevent this. Now it has started overflowing again today and he has come back and confirmed that it is indeed coming back up from the HW tank into the header tanks because of a failed NRV inside the spare shower unit.
This is never ending!
We will be fitting a new one of the original shower tap with the handset and rain head and hopefully that will be then end of this!
Your first post stated
"We had a brand new pumped shower installed over the bath 2 months ago as part of a refurb and, in the last week the HW has failed totally"., it was found full of debri recently?, did it originally work OK from both handset & rain head?. Is the new one being replaced under warranty?,
"We had a brand new pumped shower installed over the bath 2 months ago as part of a refurb and, in the last week the HW has failed totally"., it was found full of debri recently?, did it originally work OK from both handset & rain head?. Is the new one being replaced under warranty?,
It was never right from day 1. We always had to fiddle about with the shower controls to get it to start the pump and then it would fail soon after. Yes, we are aiming to get it replaced under warranty but it was ordered on the builder's account so they supplier will only speak to him due to data protection.
You need to get a new plumber.
Andy
Andy
When it is installed then remember ~ 0.8LPM must flow from either the handset or the rain head under gravity as this starts the pump, if no or < this 0.8LPM then that new shower isnt suitable for that positive head pump possible because the shower non return valve requires a greater head than is provided now. Did water flow under gravity originally from the shower??.
??
That was the point I was making, given a rain shower is higher up and has small outlets it needs a higher head of pressure to flow enough for a positive head pump to start. The new shower probably has a higher flow rate with the available pressure, that's enough now to start the pump, that and given that it sounds like they didn't flush the system clean before the pump was connected, that then damaged the old pump, compounding the problem. Gravity systems are notorious for fluctuating pressures and flows, that can play havoc with a pump if the flow is close to its activation point
My concern now would be that given the number of issues they originally introduced, if they now get it working and then months down the line it starts acting up again, where then?
Update. Looks like this is solved.
The builder purchased and fitted (no cost to us) a new shower tap unit several weeks ago and now it works fine every time on both handset and rain head. The pump consistently kicks in straight away.
It really does look like this was all caused by debris from the CW tank blocking the original tap unit.
The builder purchased and fitted (no cost to us) a new shower tap unit several weeks ago and now it works fine every time on both handset and rain head. The pump consistently kicks in straight away.
It really does look like this was all caused by debris from the CW tank blocking the original tap unit.
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