guess i should have fitted an accumulator ?

[simonfraser]

just replaced my 20 yr old water pump for one of these

https://www.tcschandlery.co.uk/whal...qhobYfgkd2AcFCYfgo2YuR_3K8fNqwREaAgm_EALw_wcB

looked exactly like the old one which leaked, but did not pulse supplying water

the new one produces a smooth flow from the calorifier, due to a head of air ?
but pulses when any cold is added

 

[vyv_cox]

My boat was built without a calorifier and only obtained one when I installed it at about 10 years old. Some recent pumps are supposedly designed so that an accumulator is not necessary but I cannot tell from the info on yours whether it is one of that type. E.G. this one https://www.jabscoshop.com/marine/p...-0292-par-max-29-pressure-controlled-pump.htm

 

[blan321]

Yes, I fitted one of those (jabsco 2.9, 12v) to replace my old burnt out water pump and took off accumulator having read the advert. Worked fine thro cold but pulsed thro hot supply via instant gas water heater. Sorted by unofficial small increase in water pressure upper limit (screw accessible but voids warranty).
Jabsco technical very helpful and agreed increased resistance to flow of water was causing the pulsing (motor cutting in and out, to be clear) and that re fitting accumulator may help, but I have found a workaround

 

[thinwater]

You really can't use a calorifier without an accumulator without problems. Water expands when heated and it has to go somewhere. In your house, it can expand back up the inlet. But in a boat, there is a check valve at the pump. The pressure can relieve through a valve, but that's a mess and it is hard on the equipment. At least in the US, it is required by the building code on land. The code for boats seems to have overlooked the subject.

Vendors keep trying to eliminate them, but they are the better solution.

 

[simonfraser]

Yes, I fitted one of those (jabsco 2.9, 12v) to replace my old burnt out water pump and took off accumulator having read the advert. Worked fine thro cold but pulsed thro hot supply via instant gas water heater. Sorted by unofficial small increase in water pressure upper limit (screw accessible but voids warranty).
Jabsco technical very helpful and agreed increased resistance to flow of water was causing the pulsing (motor cutting in and out, to be clear) and that re fitting accumulator may help, but I have found a workaround

Tnx, where is this screw ?
Which way did you turn it ?

 

[matthewriches]

You can still fit one? I'd say it's a no brainer and takes away any pulsing or sploshing issues.

 

[simonfraser]

i can, but various bits of the engine have to come off for access, so a minor screw adjustment would be simple
assuming i can get to the screw ......

 

[blan321]

Jabsco pump has a small blue 4cm box on end with leads, that's the pressure switch. Small screw holds cover on. Remove screw and housing, reveals another screw with paint witness Mark, that's the one. Turned small amount clockwise to increase max pressure. Sorry if different to yours.

 

[Plum]

My boat was built without a calorifier and only obtained one when I installed it at about 10 years old. Some recent pumps are supposedly designed so that an accumulator is not necessary but I cannot tell from the info on yours whether it is one of that type. E.G. this one https://www.jabscoshop.com/marine/p...-0292-par-max-29-pressure-controlled-pump.htm

That's the pump I have just fitted, no accumulator and nice steady flow although on very low flow rate the pump cycles every 2 seconds but which i find very acceptable.

Www.solocoastalsailing.co.uk

 

[simonfraser]

Jabsco pump has a small blue 4cm box on end with leads, that's the pressure switch. Small screw holds cover on. Remove screw and housing, reveals another screw with paint witness Mark, that's the one. Turned small amount clockwise to increase max pressure. Sorry if different to yours.

tnx, np if it is different, that's my problem
Whale pump does not have such an external box.
will take it all apart again and and fit an accumulator, the cold water pulses all the time, annoying.

 

[PaulRainbow]

You really can't use a calorifier without an accumulator without problems. Water expands when heated and it has to go somewhere. In your house, it can expand back up the inlet. But in a boat, there is a check valve at the pump. The pressure can relieve through a valve, but that's a mess and it is hard on the equipment. At least in the US, it is required by the building code on land. The code for boats seems to have overlooked the subject.

Vendors keep trying to eliminate them, but they are the better solution.

[pedant mode]

The thread isn't about the calorifier, it's about the water pump cycling due to the lack of an accumulator.

What you refer to above as an accumulator is actually an expansion chamber. Accumulators are fitted in the cold water circuit, after the pump, to stop the pipe cycling. Expansion chambers are fitted in the hot circuit, to stop the expansion issues you mentioned.

The non return valve (check valve) is normally fitted at the calorifier.

[/pedant mode]

 

[Caladh]

Thanks for that Paul. Having just removed an accumulator from my setup with a new type bypass pump, after reading some of this thread I wondered if I might have an issue with the hot water side !!

 

[simonfraser]

Just fitted my accumulator, 3hrs due to poor access, pulse gone