New Shower and Pump problem

[sidnee]

Hoping someone can guide me.
I fitted a new shower cubicle with a Salamander pump yesterday. I incorporated the pump because the header tank is only about 600mm above the shower rose.

The pump is situated at the foot and at the side of the hot water tank, which sits on the same floor as the shower cubicle and is about 1.5 metres away.

When I commissioned it yesterday afternoon, going through the instructions as per Salamander pump, I cleared out any debris on hot and cold side of pump by flushing water through from supply, catching in a bucket. Then refitting filters.
Then fitted the feed pipes to the shower and hot and cold water ran fine to shower although slow.
Then ran shower on full cold, then full hot for about 6 seconds each, three times, with pump running, using the electric feed to stop and start the pump and change the temp setting each time.

Then I ran the shower as normal, checking main rose, hand-held rose and massage jets. everything was working hunky-dory. Temp/on-off tap working fine also.

After a couple of hours, after clearing up, etc, I came to use the shower - no cold water! It wouldn't flow without the pump, it wouldn't allow the pump to run, and if I turned to hot water only then slowly turned back to central position or cold the pump stopped.

So the hot water runs without the pump, albeit slowly, and starts the pump OK and then decent pressure, but the cold water: nowt, nothing, with or without the pump. The pump doesn't run, obviously, if the temp regulator is turned even slightly onto the cold.

I'm hoping to take a look later today, otherwise it'll most likely be Monday.
I assume, that either, there's some dirt blocking the cold, perhaps at the filter on the pump, even though it was flushed out.
Or I've somehow got an airlock in the cold water supply, but it's difficult to see how.
Or somehow the cold water flexible pipe has been crushed when I pushed the cubicle back to the wall, even though there is plenty of space and it's difficult to see how.

I have connected the hot and cold to the correct sides of the temp mixer valve as indicated by the instructions.

 

[Madrab]

Need to be methodical here, you obviously aren't getting enough flow to activate the pump for some reason. What pump is it? 600mm is right on Salamanders limit for some of their pumps to give enough flow to activate the flow switch, if I remember - min req is 2l/min.
You need to start at the shower feeds and check if there is flow up to the shower, if not then pulling off the cold outlet at the pump and see if there's enough flow.

 

[sidnee]

Hello, and thanks for your reply.
I cannot remember the model of the pump. It is a Salamander positive pressure hot & cold pump. I think it was rated for only one shower, but I am not sure about that.

According to the instructions 600mm below the cold storage tank and 1 l/min is sufficient. (The pump is about 2.5 metres below cold storage tank) But the main shower rose is only about 600mm below storage tank. And it worked fine yesterday.

The hot tank is fed from the same header tank as the cold is taken from, but the cold header is above the shower cubicle.
That is the weird thing, the hot and cold are fed from the same cold storage tank, (the cold fed from the opposite end of the tank to the hot feed to the cylinder, as per recommendations). The hot feed obviously has more bends, and pipework than the cold, the cold feed to the pump runs alongside the cold feed to the cylinder, and feeds the pump where the cold feed to the cylinder enters.

And it was working fine when I commissioned it yesterday!

I'll look at it possibly later or Monday.

 

[picasso]

More likely to be a sticky nrv, I would change the pump for a negative head one, your going to get grief in the future with the tank being just on the limit for minimum flow.

 

[sidnee]

A quick update:
The problem was squashed flexible at the back of the cubicle.
It was OK when the cubicle was out by about 100mm, but pushing it back that last little bit squashed the flexible. Perhaps with a decent pressure the cold water may have forced its way through, but at the reduced pressure that I am working with, a slightly crushed flexible was enough to severely restrict the un-pumped flow, thus not switching on the pump.
They were only 400mm long, as supplied with the cubicle but I've now changed them for 800mm long flexibles to provide that extra flexibility and manoeuvrability.

There was a little bit of debris in the cold feed filter to the pump, but not enough to cause any problem.

Thanks to those that offered assistance.