Digitizing the old Enviro Dial-A-Fire Convection blower Dial Control. :-)

Hello

Anyone try this with their Enviro EF-2, EF-3, Napoleon NPS40, Harman, or Travis Lopi or Avalon AGP pellet stove or older model stove with a knob control for their distribution blower?

Alot can be said for these old dial controls. They are simple to fix, easy to use and last along time because they are not easily suseptable to power surges.

However when using potentiometers in an older electronic component circuit instead of triacs, you do loose some peak voltage to the blower and there is a higher current draw due to the greater electrical resistance of the pot. This means more watts and more money in electricity.

This explains why Triacs are used in newer control panels. They can be biased with low voltage and switch the high 120 vac with no losses.

This voltage and current meter display shows proof of the above statements.
Note: The non linearity of the voltages vs the knob setting. Typical with potentiometers. That is whay they had pots with what they called Audio Taper. LOL

Pics below show convection blower voltages for different settings.
Pic 1 - MAX room blower setting.
Pic 2 - Guage shows 96 volts drawing 22.5 amps
Pic 3 - MIN room blower setting
Pic 4 - Guage shows 33 volts drawing 2.2 amps
Pic 5 - 1/2 room blower setting
Pic 6 - Guage shows 38 volts drawing 3.8 amps
Pic 7 - 3/4 room blower setting
Pic 8 - Guage shows 44 volts drawing 4.7 amps

 

22 amps?Were you an electrical engineer?I'd be embarressed.

 

Hello

No need to be embarrassed Bob.
The control for the stove is 18 years old, and the potentiometer seems a little flaky (Which can be highly resistive) at the high end and on the Max dial setting.
The room blower may be that old also.

So I changed the reluctor tonight to the other AC leg and got the following.
92 VAC at 20.8 amps on the Max setting. See pics below:
Being around 20 or 22 amps may not be enough to trip the 20 amp circuit breaker.

It may be a sign the control and circuit is going bad. So if someone could take the same measurements on another EF-2 or EF-3 it would be very helpful here.

 

At 20 amps you would have smoke,period.You are doing something wrong.

 

There is only one way to hook up this gauge, so I did nothing wrong. What do you suggest?
Do you have a knob control for the room fan on your stove Bob?

 

A fluke meter.

 

Cannot measure the resistance of the Pot using the 2 wires coming out of the module because they are the output of the SCR. So what type of measurment are you looking for?

 

I am not looking for anything other than telling people a pellet stove cannot draw 20 amps without catching fire or burning up some wiring or another electrical device.Buy a good multimeter,hook in series and see what the true amp draw is.Buy the way,older integras like mine have an on/off switch and one knob/control.The mass air flow sensor takes care of all three motor speeds,a replaceable prom controls programming.There are 2 trim pots on board to adjust for installs.Not bad for 1988 technology.The newer ones had a more complex board for 7 day multi programmable temps and startups,still pretty much normal in european stoves,becoming more so over here.

 

Hooking a meter in series to measure current is only done for low voltage DC. Usually higher current and AC current is measured by a clamping meter or reluctor that measures the current in the magnetic field that is produced.
A fluke AC Current meter such as one of these are good measurement tools for high or low current. However the small AC current we are measuring here should be fine with the meter I have.
http://www.transcat.com/Catalog/pro..._medium=base&gclid=CLX02dbG-r4CFY1lOgodhSYAGQ
Or
http://www.transcat.com/Catalog/productdetail.aspx?itemnum=CNX I3000&utm_source=google&utm_medium=base&gclid=CN7Q74LH-r4CFc1QOgodRXIAzg

You can still put a current and voltage meter on your room blower. Even that would be a compaison?

 

You're right about the ac and series,was thinking clamp on.Thats not your clamp on in the pictures,have you tried it?

 

I was thinking of doing that. It is costly but would be a very nice update.
See before and after below.
It took me a week to free the rusty cleaning rod and the rake. Then I put in a new rod that came with the missing nuts! Now the rod pushes and pulls with ease!
The pre-2008 EF-3 and EF-2 with the large 3/4" drive auger and bearing are the most rugged and work much better with the Nylatron bearing upgrade to make a stove that will not die!