Paloma water pressure problem

[silverbuttocks]

Hi All!

 

My wife and I have a 63 foot narrowboat. We recently had a Paloma hot water boiler replaced (the old one didn;t work when we bought the boat a few months ago). The Paloma is situated in the galley, around one third of the way along the boat from the bow. The water pump is on the inside of the boat, on the other side of the wall from the cratch. Our bathroom is another third of the way down the boat. When we turn on the hot water tap in the bathroom the Paloma (set on highest temp) ignites (only when water turned on full) and we get hot water - but too hot to shower under. If we turn the cold water on - even just a little - then the Paloma stops burning (presumably because of a lack of water pressure), so then we have cold water. If I turn down any of the settings on the Paloma (down to 'two flames', or down to anything less than '5') then it does not ignite even when hot water tap is turned on full and cold water off. So, we have either hot or cold water, but no happy medium.

 

We are new to narrowboats! Can we turn the water pressure up on the pump? Will this cause leaks if we do? Can we make the Paloma more sensitive to water pressure? Is there anything we can do to solve this??

 

Any advice would be much appreciated!!!

 

Cheers!!

[BEngo]

Do you know if the hot water system used to work OK?

 

What happens when you turn on the galley hot tap (full on)? Does the Paloma ignite and does it stay lit if you vary the temperature setting?

 

What is the pump?

 

 

The Paloma maintains a water pressure drop across a diaphragm. The size of the pressure drop is controlled by the temperature knob. The greater the pressure drop the lower the water flow rate and the hotter the water. If there is not enough flow through the heater there is not enough pressure drop and the gas to the main burner is turned off. When you turn on the cold flow and it mixes with the hot in the shower the pressure drop across the Paloma will reduce and it will go out.

 

The lack of flow could be caused by the pump not being big enough (probably unlikely if the system used to work OK), a blockage in a filter, wear on the pump or a blockage (scaling up) in the shower head/tap.

 

If the galley hot tap works OK it's not something before the Paloma. Start by taking the shower head off the hose. If it works then either descale the shower head or buy a new but simple one- no variable jets or aerators. If the shower hose alone doesn't work then borrow a new hose and try again. After that it's dismantle the shower mixer unit and check that it is not scaled up.

 

 

If there's no hot water in the galley then look at the filter before the pump and at the pump for leaks.

 

Other things to check are that the gas regulator is reasonably modern and that it is working at it's correct pressure. They do have a finite life, about 5 years. Checking it will involve putting a manometer/pressure gauge on the gas test point so you may need a professional.

 

 

N

[MtB]

The lack of flow could be caused by the pump not being big enough (probably unlikely if the system used to work OK), a blockage in a filter, wear on the pump or a blockage (scaling up) in the shower head/tap.

 

 

Could also be caused by a hole in the diaphragm. In fact my money is on it being a daiphragm fault. A new diaphragm may not be available separately, I have an idea you have to buy the whole 'water section' containing it. About £50 on ebay, or a bit more direct from Morco.

 

MtB.

P.S. except I've just noticed it's a Paloma! Contact Paloma Bob on here. He fixes Palomas for a living.

[smileypete]

How many litres per minute do you get out of the taps into a bowl or bucket? Usually a 10 litre per minute pump will do for a Morco and the like but anything less might not be enough.

 

If the pump cut out pressure is too low it will cycle off and back on prematurely, but adjusting the cut out pressure won't help if the flow is too poor in the first place.

 

Best to rule out water supply probs before paying someone to look at the heater. Usually in the heater install/service manual there's a section on fault diagnosis tho it can be a bit cryptic sometimes

 

cheers, Pete.

~smpt~

Edited August 25, 2013 by smileypete

[silverbuttocks]

thanks everyone! i think it must be the pump, on its last legs. hot water works much better in the kitchen next to the paloma, but I still only get about 7 litres pm there, and only about 5 l pm in the bathroom. the pump is a flojet that should deliver 12.5 litres pm. a friend suggested the pressure switch is knackered, which sounds plausible. sometimes it does this thing now when the pump sort of stays on, or at least with a sort of background hum and a hiss of water. there are no leaks though and it does this even if i turn off the supply on the tank-side of the pump. the pump is a couple of years old or more so i guess that i just need to replace it. i was going to get a jabsco parmax 2.9gpm which should deliver 11 litres pm. what does anyone think? is this powerful enough for a 63 foot narrowboat or should I aim to get something which delivers a bit more pressure, and if so any suggestions. the parmax 2.9 is only about 50 quid off ebay which does seem suspiciously cheap...

 

thanks for your replies to my first post!!! much appreciated all of you