Monitor 41 test fuel pump?

[HayZee518]

sequence

The sequence is the same on all vented heaters.
Unplug heater, plug it back it. This resets the computer.
Press the on-off to ON.
Combustion fan is the first to come on, the last to shut off. Igntion heater comes on.
After a 300 second purge, if all the safeties are closed, the fuel pump turns on and pumps fuel to the burner mat.
When a flame is established, the flamerod circuit takes over and confirms a flame.
The heater pot starts to warm up for about 45 seconds, then the pump shifts into high, the damper flapper opens all the way.
The heat goes into high, all burner lights are on.
The circulation fan might be on low, then shifts to high output.
When your setpoint is reached with a four degree overshoot, the heater goes into idle, the fuel pump shuts down then flame goes out. Combustion blower stays on for about thirty seconds.
Then it shuts down.

[EDNY]

You guys are great..thanks. I see that the transformer and flame detector are on the 2 amp fuse. Replaced the transformer..now I need to look at the flame detector My next post may be offering a bunch of parts!

Ed

[EDNY]

Looks like time to throw in the towel. I did look at the circuit board, there are (2) Bridge Rectifier Diodes (learned this by during a search), the upper one has zero resistance. The lower ohms the same as both rectifiers on my other main board and it's tied into fuse 1. May solder in a new one.


Upper left (yellow circle)

[HayZee518]

bridge rectifier

it's better to ring out the rectifier out of the circuit because you are also measuring everything downstream of the DC output of the bridge.
AC is impressed at two opposing corners of the bridge. DC is taken off the other two corners, one being positive - the other being negative.
If you can, disconnect the secondary of the transformer and see if the fuse blows again. As an alternative, get a resettable miniature circuit breaker with a set of alligator clips, clip it to the fuse terminals and try a test. It's cheaper than buying glass fuses all the time. I'm sure you can find one on AMAZON.
Its useless to go to RADIO SHACK. They have very little in stock for components.
As far as the transformer goes, what ever the secondary sees, a corresponding value, only higher, will be present at the primary.

[EDNY]

Good stuff! This reminds of the problem a buddy had with his Miller Tig welder, the main board went out which is common on that model. At $200 for repair and $500 for a new one I did some Internet searching and found which circuit part was the problem and for about $8 repaired the board. There is a similar problem with GM instrument clusters and ABS brake modules going out..in both cases via the Internet learned which circuits only needed to be resoldered...and they were fixed without parts. I'm sure there is a very common fix for the Monitor boards.

Ed