Recent Harman Combustion Blower Upgrade! but why?

[Don2222]

Hello

After working on a few Harmans, I found the new Harman Combustion blower is now 1.75 Amps and the older blowers are only 1.50 Amps. Harman does change the part # on upgrades and sure enough, the new blower does have a new part number!

If anyone has any insight as to why this upgrade was done, please let us know.
Did Harmam put out a Service Bulletin that explains it?

See pics below for proof!

Pic 1 - Old Star date 12/12/2008 1.50 Amp Part # (BM)2524-A1506T-1204
Pic 2 - New Star date 11/05/2013 1.75 Amp Part # (BM)2524-A1756T-1371

Time to update the Harmy's again! LOL

 

[Don2222]

Hello

One of my good dealer friends helped with extracting the answer here.

There is a small white screw next to the Ignighter light used to adjust the combustion fan to make up for voltage irregularity where the stove is installed.
According to the instructions I have attached, the white set screw is only to adjust the combustion blower when the Circuit Board automatically sets the combustion blower to low draft in test mode. (Draft should be between 0.30 and 0.35 WC)
Turning it to the left will increase the exhaust blower speed/voltage.

However, It is important to set the low draft using a digital manometer so the draft fan does not bottom out. (Draft should be between 0.30 and 0.35 WC) See instructions below.

It seems to me that the stove does vary the combustion blower between low and high draft.
I can hear the increase when the Temperature knob is turned up
The combustion blower speed is also automatically set in room temp mode as the heat ramps up or down and manually in stove temp mode as the heat level knob is turned up.

Therefore, in room temp mode, getting the right set temp on the temp dial would be much easier since adjusting the knob would not be so coarse and difficult to do as it is now. Sounds like a really nice upgrade! I want one!

One other side note is that the circuit board if old, would also have to be upgraded to have the wider voltage control over the blower. I already noticed a difference when I did mine!

Thanks for the help on this!

 

[tjnamtiw]

It appears that Quadrafires according to recent posts here (don't know if you followed them, Don) also made changes to their combustion blowers going from 11 blades to 9! Same RPM's and diameter I assume to get it in the hole.

 

[Don2222]

It appears that Quadrafires according to recent posts here (don't know if you followed them, Don) also made changes to their combustion blowers going from 11 blades to 9! Same RPM's and diameter I assume to get it in the hole.

Same amps and CFMs?

 

[tjnamtiw]

good questions, no answers.
With same rpm's and fewer blades, one has to assume fewer cfm. The OP on one post was complaining of lazy flame after replacement.

 

[MX2]

What model is this upgrade applicable to? All? Thx.

 

[Don2222]

What model is this upgrade applicable to? All? Thx.

Not all, I know it will not fit the Harman Invincible FS. LOL
These are the Harman stoves its compatible with:
P38+
P43
PC-45
P61
P61a
P68
PF-100
PB-105
HF-60
Advance
Accentra FS & Insert
Invincible RS
Invincible Insert
XXV

 

[Don2222]

Hello

Just took a pic of the motor tag on the 12 y/o P61. It has a Jakel 1.70 amp motor!