Takagi TK-Jr won't stay on

Users who are viewing this thread

activa

New Member
Messages
5
Reaction score
0
Points
1
Location
Pennsylvania
My Takagi TK-Jr was installed in our new home about 7 years ago. It worked fine until recently when it started to shut off occasionally. When it did, the LED was blinking three times, indicating no ignition. I followed the instructions to clean out the heat exchanger (as I had done shortly after we moved into the house because all the plaster dust had clogged it) and also discovered the high limit switch had tripped. Takagi tech support suggested descaling the exchanger, which I did, and I can't believe the amount of crud that came out!

So I figured I'd be in good shape, but now it shuts off if there's too much demand (e.g. when the radiant floor pump is going and a faucet is open). When it does, now the LED blinks FOUR times, indicating either a pressure switch or fan issue. In addition, there's green liquid dripping from the condensate port when I fire the unit up. Also, the fan seems to be "throbbing" or not running smoothly.

Is the pressure switch supposed to detect too much back-pressure when the fan is running? Could the vent be clogged? Not sure what to make of the green liquid.
 

activa

New Member
Messages
5
Reaction score
0
Points
1
Location
Pennsylvania
Ok, so I figured it out... the original vent pipes had rotted out (the builders had decided to route it about 16' along the ridge of the carport rather than put a hole in the roof). So I had replaced it (the second time) recently with dryer vent, which had sagged, and the cold weather had formed a lot of condensate, which had gathered into the sag, partially blocking the airway. The vent fan was pushing the air enough under low pressure, but when the unit increased its output the blockage was enough to shut the unit off. I cleared the condensate in the vent pipe and now it's working perfectly.
 

Dana

In the trades
Messages
7,889
Reaction score
509
Points
113
Location
01609
Ok, so I figured it out... the original vent pipes had rotted out (the builders had decided to route it about 16' along the ridge of the carport rather than put a hole in the roof). So I had replaced it (the second time) recently with dryer vent, which had sagged, and the cold weather had formed a lot of condensate, which had gathered into the sag, partially blocking the airway. The vent fan was pushing the air enough under low pressure, but when the unit increased its output the blockage was enough to shut the unit off. I cleared the condensate in the vent pipe and now it's working perfectly.

The vent pipe for a Takagi JR needs to be stainless steel (Z-vent) for code & safety reasons. See page 7 of the manual, where it states:

This unit requires 4" category III approved single wall stainless steel vent pipe, or any other Catetory III approved non-combustible corrosion resistant material.

Also note where it states:

The maximum length of the exhaust vent piping must not exceed 35ft. deducting 5 ft. for each elbow used in the venting system. Do not use more than 3 elbows.

That's exactly what you have, rigghhht? (Thought not.)

Sixteen feet of Z-vent is insanely expensive (which is why they cheaped out), but this is a hazard! Z-vent does not rot out, so you must have (best case) B-vent or worse. And, even it it only has 3 elbows you're probably banging on (or exceeding) the total length limit, which will also affect operation.

If you can go up through the roof with it with a much shorter run, that's the right thing to do. As currently vented it is is a very real carbon monoxide hazard. Hopefully you have carbon monoxide detectors every where, and they aren't past their expiration date?

The expense of Category III venting for any distance usually tips the balance in favor of condensing equipment, which can use PVC vent pipe at a tiny fraction of the venting cost, which can cost as much as another Takagi Jr. if running 16'+ with it.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks