Replacement water pump causing problems

[adagio]

My Jabsco water pump started leaking so rather than use a service kit, the pump is 7-9 years old, I thought I would replace it for a new one, like for like, and keep the other for a spare. No problem fitting the replacement pump but it seems it is pumping at a higher pressure and using the shower, for instance, the pump is pulsing quite dramatically to start with and the same happens when using the washing machine. If we open say the sink tap full on no problem. In addition to the shower, sink, and washing machine, we have the bathroom sink and cassette flush. Would I be right in thinking we need an accumulator to solve the problem?   

[Tony Brooks]

5 minutes ago, adagio said:

My Jabsco water pump started leaking so rather than use a service kit, the pump is 7-9 years old, I thought I would replace it for a new one, like for like, and keep the other for a spare. No problem fitting the replacement pump but it seems it is pumping at a higher pressure and using the shower, for instance, the pump is pulsing quite dramatically to start with and the same happens when using the washing machine. If we open say the sink tap full on no problem. In addition to the shower, sink, and washing machine, we have the bathroom sink and cassette flush. Would I be right in thinking we need an accumulator to solve the problem?   

 

It won't solve it, but it will alter the length of the on-off periods.

 

Pumps cycle when the rump output is greater than what can flow from the outlet. Hence, a full open sink tap gives no problems, but things with some kind of restriction, like the shower head, to flow will.

 

Did you by any chance fit a new inlet strainer, if so the old one was probably partially blocked. Otherwise, the valves on one or more of the old pump's pumping chambers may have jammed open, reducing the old pump's output volume.

[Detling]

Same happened to me, with an acumulator as said the on/off periods are just a longer but still there, new pump is also a lot noisier. The old pump had developed an internal leak and wetted the motor so it rusted solid in the first lockdown.

[adagio]

Hi Guys, thank you very much for your thoughts on the matter, especially you Tony who is an amazing font of knowledge. Since seeking your council I have had a long conversation with Jabsco who by and large agree with you Tony on the subject of accumulators, why am I not surprised. So I'm gong to install an 8l accumulator which Jabsco suggest will help. We'll see. Thanks again for your help.

[system 4-50]

On 05/09/2021 at 17:30, adagio said:

My Jabsco water pump started leaking so rather than use a service kit, the pump is 7-9 years old, I thought I would replace it for a new one, like for like, and keep the other for a spare. No problem fitting the replacement pump but it seems it is pumping at a higher pressure and using the shower, for instance, the pump is pulsing quite dramatically to start with and the same happens when using the washing machine. If we open say the sink tap full on no problem. In addition to the shower, sink, and washing machine, we have the bathroom sink and cassette flush. Would I be right in thinking we need an accumulator to solve the problem?   

You've said like for like. Was this exact or have you exchanged an accumulator-free type for an accumulator-requiring type?  Jabsco have made both in the past.

[adagio]

I exchanged like for like models, and Jabsco confirm they’re identical but made no mention of any accumulator. It was only when I explained the issues they felt fitting an accumulator would help solve the issue providing it was of sufficient size, I.e., not a 1 or 2 litre model. Talking them through our usage and outlets they suggested an 8l. The failed pump, which was fitted prior to our ownership, was fitted without a filter and the new pump came with a filter in the box so I fitted it. The filter also affects the pump.

[Tony Brooks]

1 hour ago, adagio said:

I exchanged like for like models, and Jabsco confirm they’re identical but made no mention of any accumulator. It was only when I explained the issues they felt fitting an accumulator would help solve the issue providing it was of sufficient size, I.e., not a 1 or 2 litre model. Talking them through our usage and outlets they suggested an 8l. The failed pump, which was fitted prior to our ownership, was fitted without a filter and the new pump came with a filter in the box so I fitted it. The filter also affects the pump.

 

In that case, I bet the old pump had severely reduced output - crud in its valves.

[adagio]

It could well have. Once I’ve got the accumulator fitted I will open up the old pump and see what the situation is inside out of curiosity. I’ll let you know what I find but it will be a while as we’re leaving the boat for a while.