Replacing a seized Salamander CTForce20PT Pump - warranty claim refused.

davidod1 · 19-11-2025 12:55PM #1

I have a Salamander pump in the hot-press. It is sited below the copper cylinder that is used occasionally to boost the pressure in the taps, especially if the bath shower is being used. Otherwise the tap pressure is adequate around the house. The house is a 1970s bungalow with a water storage tank in the attic, where there is also an expansion pipe fitted.

The Salamander pump seized, and Salamander authorised an engineer to do a house call to check; and if necessary replace the pump. However, the engineer would not replace the pump stating that, as there was not a device to prevent air from being sucked back into the system, the warranty was void.

Is this reasonable, does air get sucked down in to the system, and if so would it not be apparent in the water flow from the taps. Anyway, if it did, is this a likely reason for the pump to seize?

Then - regarding replacing the pump, what make would be a suggested model to fit instead of the Salamander pump?

Thanks for any help or suggestions.

John.G · 19-11-2025 02:06PM

If air was being sucked in then it would normally only be apparent in the hot taps.

Can you post or describe where the hot supply from the cylinder to the pump is taken off and also show any other hot take off(s).

It is faily normal to do it like this, with a surrey flange or the like, the pump HW supply is fed from the dip tube and out the side of the flange, the vent and any other hot users is taken off the top of the flange.

davidod1 · 19-11-2025 02:39PM

Thanks John.G for the reply.

I've not, nor has anyone else, been aware of any air or spluttering from any of the taps, hot or cold.

The hot and cold water feeds that were heading to under the floorboards were cut and the pump was spliced in to both feeds, putting it inline. All seemed to fine with it for just over two years, that is, until it seized.

I'll post a photo later.

10-10-20 · 19-11-2025 03:19PM

Cavitation is the name of the process where entrapped air in the water will erode the impeller and start causing it to break apart. It would look like somebody hit it with a sand blaster, all of the surfaces would be worn and you'd also see pitting. Might be worth investigating the impeller area.

The Continental Op · 19-11-2025 04:15PM

https://www.boards.ie/discussion/comment/124001092#Comment_124001092

But would that cause the pump to seize?

davidod1 · 19-11-2025 05:49PM

Thanks 1-10-20.

The top of the cylinder with the vertical 'expansion vent pipe' and the horizontal feed line to the left. At one time there was a back-boiler installed, but that is now gone and the lines bridged.

The bottom line seems to be that I should really put a flange or valve on the system. So the next question is what type, and exactly where?

The next question is what make of pump has been found to be robust and reliable, and hopefully can it be plumbed into the system in same manner as the Salamander pump? BTW the pump is located about two meters below the hot water line supply shown above.

John.G · 19-11-2025 06:58PM

Stuart Turner have a great name, you may need a negative head pump if you havn't enough flowrate to start the pump without it, like from a shower head.

Even though air ingress didn't occur and even if it did, it shouldn't cause pump seizure, I wouldn't dream of installing another pump without installing that Surresy flange or likewise, otherwise the same excuse will be used if trying to claim under warranty for any issue.

10-10-20 · 19-11-2025 07:00PM

https://www.boards.ie/discussion/comment/124001241#Comment_124001241

If they damage the components of the impeller and cause it to disassemble fail, then for sure.

https://inlinesales.com/how-cavitation-of-pumps-can-damage-your-system

John.G · 19-11-2025 10:10PM

https://www.boards.ie/discussion/comment/124001666#Comment_124001666

A interesting article, including this……….

What is ‘false’ cavitation?

This is a situation in which a pump sounds as if it is cavitating, but is not. Instead, the pump is having to deal with entrained air bubbles, which present no damage to the pump impeller.

davidod1 · 19-11-2025 11:33PM

Who would have thought that there could be so much science in 'bubbles'.

I think the pump issue must have been caused by cavitation, so l will feel justified in having a Surresy flange installed. Also, I will have to make the decision on whether the replacement pump should be a negative head pump or not. There is about 1200mm head of water above the cylinder top, so I would think maybe not.

Thank you all so much for the instruction on cavitation and the hardware advise, all very much appreciated.

John.G · 19-11-2025 11:56PM

You can check that out now (re negative pump) with the existing (seized pump), locate the highest point user where the water issues from, ie a shower head, with the shower head in place in its normal position and the shower temperature control in its usual position put the shower in service, you will obviously get a very reduced flow, hold a container under the shower head and at exactly the same time start your stopwatch, exactly 1 minute later, to the very second, remove the container, measure this with a 1 lire milk bottle or whatever to give the flowrate in LPM, do this with both the hot and cold supply to the shower, I think the positive head Stuart Turner requires 1.0LPM to activate the flow switch to start the pump. The SalamenderCT Force 20PT is only suitable for positive head, gravity fed systems. (but no harm to check out those flowrates)

Something else, the temperature of the hot water must not exceed I think 65C or else the plastic impeller can deform with consequent no pumping or/and pump damage.

davidod1 · 20-11-2025 01:19PM

I measured the water flow for both the hot and cold flow from the shower head and both were pretty much on 1.7 lters per minute. That would seem safe to me for a positive flow pump. Together with the Surresy flange fitted, I should be safe for another few years.

Many thanks for all the help. 😁

Dave

Replacing a seized Salamander CTForce20PT Pump - warranty claim refused.

Comments

What is ‘false’ cavitation?