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parney · Joined: 03 Jul 2004 Posts: 3 Location: essex

History of Problem:

1) We purchased the pump in March and had it installed in April as part of a bathroom upgrade to include a thermostatically controlled shower system. It was quickly established that a negative head solution was required.

2) Pump Was installed and commissioned by a plumber.

3) Pump was fine for about three days before it started “squealing”, normally between 1 and 3 minutes into a shower.

4) Water runs through a new Triton Tay Thermostatic Mixer Shower system. We use it at 38 degrees C or below.

5) Spoke with technical support on phone...After guy heard it he told me it sounded like the hot water was set too hot and to check the hot water cylinder temp. I did and it was set to 60 degrees. (65 max recommended in their instructions)

He then said it sounded like, I quote his words “the high temperature of the water was causing the resin to leach from a mechanical seal within the pump” and that “I should turn the temp down to 55 degrees”. If it still continued after three days then I should call him back.

6) It did continue so I called back the Technical Helpline and they arranged for an Engineer from to come out.

7) Engineer came out, checked the system, replaced the pump and flexis with and concluded the following in the report: The Essex or Techflange MUST be used for the hot pump supply in this situation.

He also observed that the c/w tank was storing 34 gallons of water.

My tank is a 50 gallon tank, but in “usable” terms, position of inlets/outlets, is currently storing 34 gallons. He told my partner that because we were running only to one shower for the pump it wasn’t an issue. At this stage, no recommendation was made to change or upgrade the tank or reposition any pipes etc.

8. We agreed not to use the pump until the Essex flange was fitted (left unwired by engineer) which we adhered to.

9) Recently, having spoken to Engineer and was informed by them that they stripped the first pump down and found that no damage had been caused to it anyway.

10) An Essex flange was fitted by a plumber and the pump commissioned as per installation instructions.

11) On the second day of use the new pump started to “squeal” as before after a few minutes of showering.

12) I contacted Technical department again and explained the problem and previous history.

13) They arranged for a second Engineer to come out (different Engineer than before).

14) Engineer came out, checked the system, and reported the low stored cold water and ball valve position (cold mains into the Cold water storage tank sited over the feed to the h/w cylinder) was causing chronic
aeration. He purged the air from pump and concluded the following in his report:

“Owing to Low stored cold water & ballvalve over cold feed this problem will almost certainly return if water storage not increased & ballvalve re-sited.

Summary:

1) The change from a Warix flange to an Essex flange (1st visit recommendation) hasn’t made any difference to the problem.
The installation instructions do NOT distinguish when one should be used instead of the other.

2) The cold water tank recommended to be changed/modified to store 50 gallons of usable water (2nd visit recommendation).

3) The ball valve is to be sited on the opposite side of the h/w cylinder cold feed (2nd visit recommendation).

Conclusion:

Having started to lose faith in their judgement between first and second visit, I decided to do a test of my own before commencing with tank changes, because I am convinced they are barking up the wrong tree blaming it on the cold water storage/ball valve situation.

This is an obvious issue for them not meeting their warranty conditions but I am sure this is not the cause in my situation for the following reasons.....

Tests have been carried out by myself , i.e. draining all hot water from h/w cylinder and turning off water heating. Then filling tank just below overflow (by holding ball valve down to fill above normal fill level. This gives 50 gallons of water I have calculated into the tank. Running a temporary pipe under cold mains inlet, so that filling water runs to other end of tank to remove risk of aeration as water hits surface just above feed to h/w cylinder. Heat water up again. Then when you run shower its fine with cold, no squealing but as soon as you turn shower to hot water, 55 deg C is highest setting (so it draws hot from h/w cylinder) after a minute or so it starts to squeal again. How can the 50 gallons in the tank and cold inlet removed from outlet to h/w cylinder be the cause.

I can only see the problem still points to their pump? Any ideas anyone?
Its driving me nuts....I just want to take a bloody quiet warm shower each morning....thats all i ask...im ok if i like them cold but if i would go anywhere near 38 deg C i was in trouble. Have had to stop using it since second engineer came last thursday Sad

Help!!!!!! im starting to smell

thescruff · Moderator Joined: 03 May 2003 Posts: 4754 Location: Bath

You missed the important bit.

Cold feed from tank to cylinder, this should be one size larger than the outlet.

Just about everything else the engineer said was correct, tank storage water should be doubled.

scruff

parney · Joined: 03 Jul 2004 Posts: 3 Location: essex

The cold feed to the cylinder is 22mm. The outlet from the cylinder is 22mm also. This is what Techflows installation manual specifies. It says it only needs 28mm diameter pipe when you are using 30 l/min or more. My shower is using no where near that amount.

Also, if you read my test part, I have explained that filling my tank with 50 gallons didnt make a difference.

1) Are you saying 35 gallons or 50 gallons is not the problem, but until I increase the cylinder inlet pipe, nothing I do to the tank will cure the squealing? My tests seem to imply this.

2) Are you also saying that their installation manual is incorrect and it does need the 28mm pipe to cure the problem?

3) Was the engineer correct in saying change from a Warix flange to an Essex flange when their manual says you can use either one? Why don't they specify which one is required for a negative head situation?

Regards

Parney

ITPC · Posted: Tue Jul 06, 2004 8:55 pm Post subject:

What type of valves are used between the cold water storage tank and the hot water tank.

I have one experience where changing the gate valves to full bore valves helped get the shower pump working properly.

What is the age of the hot water tank? Could there be a lot of scale in the bottom of the tank - also retricting flow of water into tank and hence flow out of tank?

The supplier / make of pump is?

parney · Joined: 03 Jul 2004 Posts: 3 Location: essex

The pump is a Techflow QT45 (Automatic Switching) Negative Head Pump.
New Full Bore valves were fitted when pump installed.
Not sure of Hot water cylinder age, but flow of hot water seems fine to shower. If it was being restricted wouldnt the pump squeal continuously not just after 3 mins then stop after about 20 secs?

thescruff · Moderator Joined: 03 May 2003 Posts: 4754 Location: Bath

email in the post if I get time.

scruff