DAB EVOSTA circulating pump?

Car99

Hi,

My grunfos alpha+ died today so a local suppliers had a DAB evosta pump in stock.

Fitted and running fine.

My question, I have it set to run at max speed setting because we have a 2500 sq ft house and the pump is located in the garage 25ft from the house and the hot water tank is upstairs in the house.

How do I calculate what setting to leave it on ?

Dtp1979

Car99 wrote: »

Hi,

My grunfos alpha+ died today so a local suppliers had a DAB evosta pump in stock.

Fitted and running fine.

My question, I have it set to run at max speed setting because we have a 2500 sq ft house and the pump is located in the garage 25ft from the house and the hot water tank is upstairs in the house.

How do I calculate what setting to leave it on ?

Leave it set to modulating. See if everything heats ok.

Car99

Dtp1979 wrote: »

Leave it set to modulating. See if everything heats ok.

Hi dtp thanks for the reply , how do I set it to modulating?

Dtp1979

Car99 wrote: »

Hi dtp thanks for the reply , how do I set it to modulating?

Not too familiar with the pump. Check the manual

corkgsxr

It's when the one with the curve is lit rather than the straight line part.

It only has 3 positions for fixed.

6 for modulation.

You just keep pressing the button to go through the positions.

Outkast_IRE

How old was the Grundfos Alpha pump ?

Just wondering as they are a relatively new pump and i would not expect one to of stopped working already.

Car99

Outkast_IRE wrote: »

How old was the Grundfos Alpha pump ?

Just wondering as they are a relatively new pump and i would not expect one to of stopped working already.

Installed and in full time use sInce 2007

Car99

corkgsxr wrote: »

It's when the one with the curve is lit rather than the straight line part.

It only has 3 positions for fixed.

6 for modulation.

You just keep pressing the button to go through the positions.

Cheers, I have it on the straight line at max speed.

The condensing oil boiler seem to be running more during for the hour the system is timed on for than with the Grundfos .

Although I could be wrong as I never paid too much attention.

On the plus side the rads seem hotter.

Would there be any harm leaving it on that setting?

Would the burner guzzle more oil?

Our usage is:

We run the heating in winter for 1.5 hour in the morning and the same in the evening

In summer it's 1 hour in the morning to heat the hot water for the days use with all other zones off.

Burning about 1200 to 1400 litres per annum on a grant condensing oil burner.

corkgsxr

I'd leave it on modulating. My thought on it is alot of the power is used to get the water moving. Keeping it moving needs less power so it can modulate down.

So saves power even in a unzoned system with no thermostatic heads.

Car99

corkgsxr wrote: »

I'd leave it on modulating. My thought on it is alot of the power is used to get the water moving. Keeping it moving needs less power so it can modulate down.

So saves power even in a unzoned system with no thermostatic heads.

I'll give that a go so.

Dardania

corkgsxr wrote: »

I'd leave it on modulating. My thought on it is alot of the power is used to get the water moving. Keeping it moving needs less power so it can modulate down.

So saves power even in a unzoned system with no thermostatic heads.

I'd question the logic behind this - if there's no zones or TRVs, the pressure should stay stable? What's the value of modulating - the pressure differential won't change...

OP: Is your system zoned, or with TRVs? If so, modulation makes perfect sense.

Otherwise, your boiler should in theory have a flow rate requirement in the manual you can match...with a bit of overhead to account for system losses

Dtp1979

What size is the boiler and how many rads?

corkgsxr

Dardania wrote: »

I'd question the logic behind this - if there's no zones or TRVs, the pressure should stay stable? What's the value of modulating - the pressure differential won't change...

OP: Is your system zoned, or with TRVs? If so, modulation makes perfect sense.

Otherwise, your boiler should in theory have a flow rate requirement in the manual you can match...with a bit of overhead to account for system losses

It's like pushing a pushing a car most of the effort is getting it moving. Once it's moving it's much easyer to keep it moving.

Same with water. Getting it up to speed might require 100 Wats but keeping it going might only be 40.

Dardania

corkgsxr wrote: »

Dardania wrote: »

I'd question the logic behind this - if there's no zones or TRVs, the pressure should stay stable? What's the value of modulating - the pressure differential won't change...

OP: Is your system zoned, or with TRVs? If so, modulation makes perfect sense.

Otherwise, your boiler should in theory have a flow rate requirement in the manual you can match...with a bit of overhead to account for system losses

It's like pushing a pushing a car most of the effort is getting it moving. Once it's moving it's much easyer to keep it moving.

Same with water. Getting it up to speed might require 100 Wats but keeping it going might only be 40.

I do agree with you - but it doesn't justify modulation.
A normal pump accounts for the startup torque to overcome the inertia of the water by having a high current draw until it is up to speed. It's why one would tend to put C curve breakers supplying a pump rather than a B rated one, to account for the few seconds of startup.
Does the set point for the pump change during startup - surely it tries to achieve a constant pressure (I guess off pump pressure)?

corkgsxr

Dardania wrote: »

I do agree with you - but it doesn't justify modulation.
A normal pump accounts for the startup torque to overcome the inertia of the water by having a high current draw until it is up to speed. It's why one would tend to put C curve breakers supplying a pump rather than a B rated one, to account for the few seconds of startup.
Does the set point for the pump change during startup - surely it tries to achieve a constant pressure (I guess off pump pressure)?

You can only buy modulating pumps now so why not leave it in modulating setting. If it cuts down how bad if it doesn't it's cost ya nothing.

For what it's worth tho iv see modulating pumps drop down to 14watts not long after startup.

Car99

Dtp1979 wrote: »

What size is the boiler and how many rads?

17 rads , grant boiler not sure of spec now and I'm away from home so can't check ..

Car99

Dardania wrote: »

corkgsxr wrote: »

I'd leave it on modulating. My thought on it is alot of the power is used to get the water moving. Keeping it moving needs less power so it can modulate down.

So saves power even in a unzoned system with no thermostatic heads.

I'd question the logic behind this - if there's no zones or TRVs, the pressure should stay stable? What's the value of modulating - the pressure differential won't change...

OP: Is your system zoned, or with TRVs? If so, modulation makes perfect sense.

Otherwise, your boiler should in theory have a flow rate requirement in the manual you can match...with a bit of overhead to account for system losses

Just two zones ( upstairs and downstairs ) and a hot water zone I guess. Three valves controlled open or closed by thermostats. One for each zone.

RJF

corkgsxr wrote: »

It's when the one with the curve is lit rather than the straight line part.

It only has 3 positions for fixed.

6 for modulation.

You just keep pressing the button to go through the positions.

Sorry lads, the one with the curve lit is for fixed curve speed setting.
The one with the straight line lit is for the six proportional differential speed settings (modulating).
I'm afraid ye had it backwards.:)

corkgsxr

RJF wrote: »

Sorry lads, the one with the curve lit is for fixed curve speed setting.
The one with the straight line lit is for the six proportional differential speed settings (modulating).
I'm afraid ye had it backwards.:)

While it goes against everything the Internet stands for your right. I read it wrong.

Dardania

corkgsxr wrote: »

RJF wrote: »

Sorry lads, the one with the curve lit is for fixed curve speed setting.
The one with the straight line lit is for the six proportional differential speed settings (modulating).
I'm afraid ye had it backwards.:)

While it goes against everything the Internet stands for your right. I read it wrong.

?