DAB Evosta pump

[Supergunn1]

HI,
I'm a newbie to the forum.

I have emailed DAB pumps but I'm not sure if they have received the email
If someone can read this email to DAB they may be able to help

HI,
I bought and fitted the DAB Evosta pump for my central heating system as a replacement for the old pump (not DAB ) which had failed.
I am not a plumber to trade but know how to fit and wire a central heating pump.
I fitted the new DAB pump with the flow arrows on the pump body facing downwards as this was the direction of the old pump but the new Dab pump looks as if it is fitted upside down.
ie the writing on the pump is upside down.
I am also confused as to what to set the three green led lights
as the instruction booklet is vague for a DIY installer.

Are these three lights the pump speed.
ie 1 light slow 2 lights medium 3 lights fast.

Could you please inform me what setting I should have these lights on.
My house is a 2 bedroom flat all on one level with only 6 radiators so not very large.
The boiler is gravity fed from the roof tank and not a combi boiler.

Everything is working almost perfectly since I fitted the new DAB pump with only a couple of minor issues that I hope you can help with.

The house is warmer than I can ever remember and the boiler and pump are super quiet so I know this DAB pump is a good product and has made a huge difference.

The radiators have been balanced and all are hot .

I have a small problem that if I have the Dab pump running with 1 or 2 green lights showing , the boiler sometimes throws the reset switch as if the pump is not getting rid of the hot water away from the boiler quick enough , this may only happen once in a full day and the boiler can be running for several hours before this happens or it can happen very soon after the initial start up from cold.

Sometimes doesn't happen at all in a full day.

If I have the three lights on everything seems to be ok the boiler does not throw the reset switch.

My concern is that if I am constantly running the DAB pump on
three green lights and these three lights mean full speed am I in danger of burning out or wearing out the pump too quickly.

The pipe work going to my radiators is microbore is this why I may need the three lights on the Pump to push the water through the small pipes quicker or have the lights got nothing to do with the speed of the pump.

Just a wee bit confused but hope you can clear everything up for me.

The system is quite old but when I drained the radiators and also the boiler to fit the pump the water coming out of the system was pretty clear with no signs of major sludge contamination.

To the forum members your help and advice is welcomed and much appreciated

Thank you
and
Kind Regards

Archie Gunn.

 

[ianmcd]

What speed was your old pump set at ? set the new one to the same , you are correct about speed 1,2,3 on your new pump with the LED

 

[spareshunter]

If you are worried about reading the writing on the pump undo the four bolts holding the head on and reorientate it to suit your fancy. It dos'nt matter as long as the arrow on the body is as previous pump.

 

[Supergunn1]

Thank you Ian and Spareshunter for your replies.

I'm not going to bother turning the pump head round I just needed to know it was fitted the correct way round.

Regarding the three lights I assumed this was the speed but the manual talks about fixed curve and proportional pressure which threw me off.
The manual is also very vague certainly not for a DIYer.

The Pump was fitted on Wednesday afternoon but the boiler cuts out and throws the reset switch out just once a day.

I have noticed that this seems to happen at the initial start up from cold and when you push the reset button back in the boiler fires up and will run all day with no further problems.
(doesn't happen all the time )

In fact it's never ran quieter and the house is warmer.

The Rads have been bled and balanced and the pump has been bled.

There is a pipe coming out of the top of the boiler which has also been bled. ( Thinking of fitting a automatic bleed valve to this )

There was a drain plug bolt inside the boiler on the heat exchanger which
I loosened and drained and the water coming out was perfectly clear.
I did this in case the water was sludgy.

Any suggestions guys to why the boiler trips the reset switch.
( This does not happen all the time )
Happens on 1,2,or 3 setting.
I thought that speed 1 would have been adequate for a small flat all on the one level with only 6 rads.
The pump is currently on speed three I was thinking the microbore piping to the rads may need the pump to work faster.

Do I maybe have to keep bleeding for a few days or try balancing the system again.
Does it just need a week or so and some bleeding to settle down.

Need to point out that the boiler is an old Glow worm.
When it's running it's perfectly quiet no noises apart from the flame burning.

Any help is welcomed and much appreciated
Kind Regards
Archie.

 

[ianmcd]

these so called energy efficient pumps start off at a low flow rate then build up depending on the system load, it is most likely that the flow is not enough to move the heat away from your boiler, an automatic by-pass may be the answer, personally I hate these new circulators

 

[Supergunn1]

Hi Ian,

First off I really appreciate your help and advice.

I agree with you on the energy saving pump.

I wanted to buy a Grundfoss but money was tight and I needed to get this done quickly.
I also had to renew the valves on either side of the pump due to them being so old I tried to shut one off and just caused a leak.

I have since noticed this morning higher up the boiler cupboard a expansion tank with a bottle valve connected to the side of it.

The black cap on the top was fully closed , I opened the black cap and some air did come out but not a lot.

I have left this opened one full turn this may solve the problem.
Need to now wait and see.

The system is very old and I have not ruled out sludge but the water ran very clear when I drained the rads and boiler.
The rads are all hot at the bottom maybe not quite as hot as at the top but they all feel really hot enough.

I want to flush the system with a good flusher and insert inhibitor but I,m afraid to maybe dislodge some sludge if there is sludge in there and cause blockages in the microbore pipes. ( maybe best left alone ) What do you think.
When it's running all day it's perfect I just got up this morning and had to push the reset button been running perfect all day since.

I remember when I changed from electric to gas central heating in my first house it took several weeks to settle down and work properly.

I will bleed the rads over the next few days and see how things go

Thank You
and kind regards

Archie

 

[Pump1]

Hi Archie,

Hopefully I can be of help, there are 2 settings for the DAB Evosta pump fixed/constant speed and proportional pressure.

Fixed/constant speed will react very much like your old fixed speed pump maintaining a constant RPM on the pump but each speed is equivalent to different head pumps, i.e. speed 1=4mtr, 2=5mtr and 3=6mtr. This mode is for underfloor systems or systems which require a constant speed.

The proportional pressure is best suited for radiator systems with TRV(thermostatic radiator valves) as the pump will modulate dependent on the resistance in the system i.e. when the radiator has reached temperature and the TRV has isolated it from the main pipe circuit there are 6 settings on this mode and the lower the setting the more efficient the pump will be.

Should you need further assistance just call DAB direct on 01279 652776.

 

[muggles]

Nice to see a manufacturer on here giving good sensible advice

 

[Alfredo]

It does seem to me that nobody has thought of how these variable pumps can affect a system that is less than perfect. When the original Grundfos Alpha came out we fitted lots, and we too found that there was a tendency in some cases for the boiler to lockout on overheat as presumably the pump had modulated and was not getting rid of the heat from the boiler quickly enough.

The old 'water chompers' may be unsophisticated, but they could compensate for an ageing system just by continuing to 'chomp'.

We ended up setting them to constant speed, which rather negated the whole point of having them. This was almost a decade ago mind you. It did resolve the problem as well.

Alfredo

 

[Pump1]

Running the DAB Evosta pump on the constant/fixed speed will consume less energy than a traditional pump, at full speed the max is only 44W!

 

[ScottishGasMan]

The grundfos unit would be similar in that it can be set to constant speed (still using about 50w compared to the old 90/110w versions) But not modulating down thus keeping the system water moving at a constant rate and avoiding overheating issues.

The only problem is when you use an auto bypass valve (which many boilers/systems require) if the pump modulates it may not have the pressure to open the ABV which also will cause over heating.

Most boilers require a set minimum water flow at all times through the heat exchangers and are not achieved when the pumps are left to modulate, (the only exeption being when the pump speed is controlled by the boiler, when the boiler knows whether it needs to be on high or low) where system pumps do not know how much water the boiler reqires flowed, without being set at a constant speed. Not the end of the world but usefull to remember when replaing old 3 speeds with new modulating units.