Grundfos shower pump faulty again

vulmac · 24-04-2020 08:15AM #1

I had a heating system upgrade iin 2016 The shower pump which pump's water to two showers in two separate family bathrooms had to be updated. The plumbing company installed a Grundfos pump. In 2018 pump became very noisy. Replaced with a new Grundfos shower pump out of the guarantee period. Had to pay for the new one . Yesterday the current pump stopped working altogether. It has been getting noisy over the last few months. So here I am three pump's in four years. We are a family of three with normal shower usage. The original pump which was replaced in 2016 had been working for more than eight years. It was not a Grundfos. Any ideas or suggestions appreciated.. Correction two faulty in four years this will be the third time to get a new one in four years

ANXIOUS · 24-04-2020 08:25AM

Had very similar experience with them, caused untold hassle.

Not main repairman will look at them, however if you call Grundfos directly they have their own repair department.

vulmac · 24-04-2020 08:37AM

ANXIOUS wrote: »

Had very similar experience with them, caused untold hassle.

Not main repairman will look at them, however if you call Grundfos directly they have their own repair department.

How did you resolve your problem thanks for your reply

John.G · 24-04-2020 08:46AM

I presume you are pumping hot and cold water with the pump. If so, then all these pumps are only rated for either a max of 60C or 65c (can't remember which), in some cases I have read that the plastic impeller warps, so it's pretty important that you have a cylinder stat fitted to avoid the above even though it seems utterly daft to have such a low temperature limit bearing in mind that 60C is recommended for legionella protection.

I think 65C is the limit.

vulmac · 24-04-2020 08:59AM

John.G wrote: »

I presume you are pumping hot and cold water with the pump. If so, then all these pumps are only rated for either a max of 60C or 65c (can't remember which), in some cases I have read that the plastic impeller warps, so it's pretty important that you have a cylinder stat fitted to avoid the above even though it seems utterly daft to have such a low temperature limit bearing in mind that 60C is recommended for legionella protection.

I think 65C is the limit.

Yes hot and cold from a gas heating system with termostat on the tank set around 65

John.G · 24-04-2020 09:09AM

Grundfos should give you some clue as to why 3 pumps in 4 years as to whether temperature related or whatever. I have read on some GB forum where warranty was refused because the temp was 68C!.

24-04-2020 09:10AM

Salamander and Stuart Turner pumps come with a 5 years parts & labour warranty. It's well worth the little extra cost for the long warranty

John.G · 24-04-2020 09:23AM

Don't think that warranty would apply if temperature related.....may be worth considering fitting a tempering valve after the HWC...... wonder what do people do if solid fuel heated HWC which cannot be controlled, have they experienced temperature related pump problems?

25-04-2020 10:31AM

Sleeper12 wrote: »

Salamander and Stuart Turner pumps come with a 5 years parts & labour warranty. It's well worth the little extra cost for the long warranty

Yes, I have a Stuart Turner pump that is around 15 years old, it is a very robust unit and still going strong despite frequent daily use.

When it failed (around 3 years ago) I contacted domesticpumps.ie (following a recommendation from a someone on board.ie). They essentially told me that these pumps will just keep on going with the help of some replacement parts that I can buy from them. As it happened it was the capacitor that failed so following a quick swap out it has been running away every since. Interestingly they sell a range of reconditioned pumps (complete with warranty) in addition to new versions.

For the record I do not work for this company or have any connection to it, I just had a positive experience with them.

vulmac · 25-04-2020 12:55PM

Thanks for the info. I contacted the contractor who fitted both of the pumps as to the warranty on the second pump as far as I remember the warranty on the first pump was one year. Waiting for him to get back to me. I emailed Grundfos and they requested a video and pictures of the base plate with the pump info. It is now a waiting game. I would not have a problem getting a better make of pump. I don't want to be in the same predicament in another two years

vulmac · 25-04-2020 12:55PM

Thanks for the info. I contacted the contractor who fitted both of the pumps as to the warranty on the second pump as far as I remember the warranty on the first pump was one year. Waiting for him to get back to me. I emailed Grundfos and they requested a video and pictures of the base plate with the pump info. It is now a waiting game. I would not have a problem getting a better make of pump. I don't want to be in the same predicament in another two years

John.G · 25-04-2020 01:49PM

Can you post a pic of the inlet connections to the pump especially the hot water cylinder take off as it's strange to get such a short life from any make of pump..o

vulmac · 25-04-2020 06:47PM

Here are the pictures as you can see the pump is on the tank

vulmac · 25-04-2020 06:48PM

Here are the pictures as you can see the pump is on the tank

vulmac · 25-04-2020 06:50PM

Here are the pictures as you can see the pump is on the tank

John.G · 25-04-2020 08:27PM

Is the hot water going to the left hand side of the pump?
Is the hot water supply to the pump taken off the "side" of the HWC? If it is then it is recommended that the pipe turns down first and then back up to avoid any air in the pump suction.
Is the pump noisy (apart from any vibration) in operation.

Also I see you have a solar installation, what is the maximum hot water temperature setpoint on the solar controller?.

Edit: Maybe should have asked first if the original pump that lasted for 8 years was installed exactly the same way as now, if so, then installation problems are unlikely to be the problem.

vulmac · 26-04-2020 02:36PM

https://www.dropbox.com/sh/vrk50z62qnlr6gp/AAAU-8wE057M69mwstW9QBiDa?dl=0

I have put some photos and video in Dropbox
The hot water comes in on the two right side inlets cold on left
The pump knocked off last Wednesday when my wife was washing her hair. I checked out the pump and it was very hot' I checked it again after i hour it works but soo noisy. I cant take a chance I have to leave it off until I get something sorted. i accept I will not be able to get anyone to sort it out until lockdown is over. I am 73 years so in high risk group. I dont know about temp control for solar panels. Only a box which displays temp in tank and roof. Thanks a lot for your responses

John.G · 26-04-2020 02:58PM

Will have a look at those photos shortly.....its the actual cylinder temps reached when the solar is on that I am interested in only to see if they are/have exceeded 65C say in the summer, my cylinder temp (with solar) often reaches 75C/78c but i have a anti scald mixer on the outlet which keeps the temp at 55C.

26-04-2020 03:08PM

whenever a person has a heart attack or mini heart attacks, they grab their chest and say, my hearts knackered. The heart (pump)is reacting to the system or blockage or issue therein. You've more chance of winning the lotto than having all the pumps go down in such a small time frame. It sounds like a process not a product issue. Noisy pumps can mean audible cavitation in general, the pumps can be starved etc. The plastic impeller if there is one, will be some kind og technopolymer or some shyte but it's up to the job if your water goes crazy hot.
was there away a problem with your pump? Grundfos would be a good brand, if It was Wilo I'd say ok but it wont be the pump it will be the set up.

26-04-2020 03:12PM

is it a positive head pump? it looks like one, flooded suction. when you say it was noisy in 2018, do you mean coming on and off all the time? or just very loud when it was on? like could you hear it come on and off even if there was no faucet on or anyone in the shower?
if the latter, your pump could easily be burning out, or the motor burning out.
If your system detects a drop in pressure caused by a dripping tap or leaky toilet, the pump will keep going on all the time cutting in when the pressure drop[ below
the threshold set by the switch, So it;s basically shortening it;s life time and the motor is burnt out. If the pump wont go anymore, the motor will be burnt out ill bet you.

John.G · 26-04-2020 03:41PM

Yes, you just can't keep throwing pumps (whatever make) at it until some one who knows what they are doing has a good look at that location/plumbing arrangement, it would be nice to see a schematic like the one I've attached as the photos don't show it.
The pump would normally be located on the floor adjacent to the HWC but it can be installed even higher up (in the loft) than yours, if properly plumbed in and that's why I asked where the 8 year old one was installed.

John.G · 26-04-2020 05:17PM

Also have a look at the attached, you will see a red line (on the right of picture) that I have drawn from where I think the HW supply to the pump is taken, it passes up past the red isolation gate valve and goes to the pump suction, can you see where the vertical pipe off from the T just above the isolation valve goes to??. I have a arrow on the red line pointing upwards.

vulmac · 26-04-2020 05:52PM

rusty cole wrote: »

is it a positive head pump? it looks like one, flooded suction. when you say it was noisy in 2018, do you mean coming on and off all the time? or just very loud when it was on? like could you hear it come on and off even if there was no faucet on or anyone in the shower?
if the latter, your pump could easily be burning out, or the motor burning out.
If your system detects a drop in pressure caused by a dripping tap or leaky toilet, the pump will keep going on all the time cutting in when the pressure drop[ below
the threshold set by the switch, So it;s basically shortening it;s life time and the motor is burnt out. If the pump wont go anymore, the motor will be burnt out ill bet you.

No it only comes on when using the shower. The only things on it is the two showers and they are only used one at a time

26-04-2020 11:53PM

is there a pressure vessel at all?

vulmac · 27-04-2020 11:15AM

rusty cole wrote: »

is there a pressure vessel at all?

I don't understand what a pressure vessel is. The complete job was done by a reputable contractor so I'm between is it the installation or pump and starting to feel like installation

listermint · 27-04-2020 11:21AM

Does anyone not like the location of the pump in relation to noise levels ? on top of a metal tank.

Seems a bit of a stupid location to mount it, if indeed it is mounted and not just sitting on the metal skin of the tank.
Not that its a cause for the failure just unnecessary noise vibration and shuffling around

John.G · 27-04-2020 11:39AM

vulmac wrote: »

I don't understand what a pressure vessel is. The complete job was done by a reputable contractor so I'm between is it the installation or pump and starting to feel like installation

Was your original pump located at a similar height??, the present installation doesn't necessarily mean that it is incorrectly installed.
Also check that there is a vent coming off the HW cylinder, if you go to your attic you should see a copper pipe going up and over the cold water storage tank and bending back down like a walking stick.

John.G · 27-04-2020 11:55AM

listermint wrote: »

Does anyone not like the location of the pump in relation to noise levels ? on top of a metal tank.

Seems a bit of a stupid location to mount it, if indeed it is mounted and not just sitting on the metal skin of the tank.
Not that its a cause for the failure just unnecessary noise vibration and shuffling around

There should be something to stop the pump moving about on the tank top and something like a anti vibration mat underneath to stop putting unnecessary strain on the pump (anti vibration) flexible hoses.
Re location: I have seen one mounted right up in the attic as per my attachment which had been working perfectly for a number of years when I last saw it.
Also re positive & negative pumps, a negative pump is only needed where the shower head (or highest draw off point) is higher than the CWST water level as a positive pump needs a small flow to satisfy the starting flow switch, the negative head pump uses one or maybe two small pressure vessels mounted on the pump body, when a tap or shower is requested on then the pressure will drop, starting the pump and the flow switch will only stop it when the flow rate falls to almost zero.

vulmac · 27-04-2020 12:09PM

John

Figure four looks the nearest to my untrained eye. The gas boiler is in the attic as is the reserve water tank . The hot water tank in the pictures are on the first floor with the pump sitting on the tank. The main bathroom is on the same floor as the tank . I dropped another folder into the pump folder in dropbox with a video which may illustrate it better. I dont expect to do the work myself but at times like this you find that contractors and suppliers alike become very evasive. The origonal pump was sitting on the floor of the hot press but with the new installation there is barely room for the tank. There is good mains pressure in the house and the hot flow is reasonable enough'. The pump is for the little extra boost.

John.G · 27-04-2020 12:19PM

Ok thanks for that and apologies for all the questions but another one, can you look for a label on your HW cylinder which will give operating pressure volume etc, trying to establish if you have a vented cylinder or a unvented cylinder As I said above, if vented then the vent will be quite evident above the CWST. (your "reserve" water tank)

27-04-2020 12:31PM

listermint wrote: »

Does anyone not like the location of the pump in relation to noise levels ? on top of a metal tank.

Seems a bit of a stupid location to mount it, if indeed it is mounted and not just sitting on the metal skin of the tank.
Not that its a cause for the failure just unnecessary noise vibration and shuffling around

I fitted a CORK anti vibration matt under the pump in our apartment and it's silent compared to others in the building which are very audible. Yes I agree a metal tank is not idea but vibration would really only be an issue in large pumps not these small compact close coupled things but you are right it's not ideal. It would add to the noise or acoustics.

Grundfos shower pump faulty again

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