Triangle Tube boiler not flowing

t300

Triangle Tube combi 199, 1 year old. multiple zones including floor heat and furnace. Woke up to a cold house. Went to look at boiler, it was showing supply and return 160/170degrees as per LCD screen. setpoint is 150. Supply and return piping gauges show 80degrees. Troubleshooting showed that the boiler internal 3way valve wasn't moving. Tech came, was supplied with the plunger for the valve not the entire valve. Turned back on, now the plunger moves about 1/4" when there is a call for heat, but still no flow. Internal pump is running, external pumps are running.

Turned boiler off for the night, next morning turn it back on, supply and return are at about 80 on LCD and piping gauges. within about 5 minutes boiler LCD shows both supply and return at 150+, but piping outside of boiler still not warming up so fluid is definitely not moving. piping gauges still show 80degrees.

- anyone know how far you should be able to see the 3 way valve plunger move? I would think it need to go an inch or so based on visuals. Can't see how it moving 1/4" would allow enough flow
- anything else that should be looked at here, anything common on these units?

tech coming back today to review and most likely call Triangle Tube support.

psb75

Possible that something is air-bound?
Usually changing the plunger is the fix for a combi mixing valve. Tech support should be able to answer your questions.

GroundUp

If there is no flow in the system, it has nothing to do with the 3 way- that's typically a closed valve or an airlock situation. Do you have flowmeters or something to measure flow? How are you verifying the lack of flow?

t300

Thanks, could be air. Initial issue happened as we were leaving for vacation so we just shut everything down. What I didn't mention and what makes this more complex, is that we have been waiting for boiler company to come down and do some repiping for a while. When the 'failure' happened, they didn't have the 3way valve part so when they finally came down this week, they did the repipe and the plunger replacement at same time, therefore full fluid drain and refill. Downside is that the 2 issues weren't dealt with separately so now its muddy.

In any event, it may be that the plunger is 'fixed' but they didn't adequately purge air. Will post again when they come back, hopefully its something simple like air lock.

to answer how measuring flow, I don't think they did, I didn't notice any tools/gauges for that. I'm calling it no flow simply because all the piping internal to the boiler is heating up super fast, but nothing outside of the boiler is at all.

kcopp

You say Radiant floor heating...
What tubing?
o2 barrier on it?
Those 3 way valves are notorious for having issues w/ Non barrier tubing and systems "mudding" up.

psb75

The first thing to suspect with "no flow" problems is air lock. Sometimes you can get things moving by boosting the system pressure (a little) at the fill valve, get the circulators operating and then close and open ball valves, working on one zone at a time. This can-- sometimes-- get the circs to "grab" fluid and help to start "chasing" the air out through the installed air emitters (Spirovent, air scoop, cannisters etc.)

t300

issue appears to be solved, was a faulty install? of the bypass valve plunger replacement. Looks like the solenoid has a little pin that should be attached to the plunger and it wasn’t somehow, so plunger wasn’t able to retract. Seems like a poor design

a couple really bad pics showing the pin.  They also added another air vent as there was definitely a lot of air in the system, but that wasn’t root cause

First is after pic, then before pic 

t300

Thank you for all the helpful posts! Always learning 

GGross

And now I feel bad because when you said "how far should i see the 3 way valve move" my first thought was that you should not see it move at all when it is attached to the solenoid, but I never hit "post comment"

t300

Ha all good, it worked out. Just got a call from the tech's company, said he was on the phone with Triangle Tube today to follow up and they told him to add an additional bypass in as it seems like a this is a common issue with the 3way valves unless you have some kind of added bypass. Would have been great if Triangle would have said this on the initial tech call! So thats getting added next week.

t300

In case its usefull to any others, the line in GREEN is what triangle tube said to add in

t300

good news bad news. it worked for a while. Then the stepper motor and plunger 'pin' disconnected again. Its just a push fit, pin has a bigger ball on the end. Plunger still moves fine in the valve housing. So the plastic piece on end of the stepper motor that the plunger pin sticks into just keeps popping out. Terrible design, not sure why they didn't use a circlip or something. If warranty provides a new stepper motor with a new/tighter plastic housing then great, if not its getting RTV'd together.

tim smith

I just fixed one that was sticky a couple weeks ago. The pin would hang up and not spring out but there problem was no hot water some times. Used some plumbers grease on the pin and got freed up. The cartridge was only a year old. Barrier tubing, no muck. But it could possibly be hanging up when trying to push in or the motor gears may be slipping. Few different options, also of course could still be air.
Tim

dhudd

I have the same issue with my combi 199, the plastic rod on the motor has become worn out to the point the plunger pin will not stay connected. Has anyone come up with a better solution that replacing with the same terrible design? This unit is only three years old and I suspect this will be a reoccurring problem given the poor design and materials used.

t300

I had a new motor put in so that fixed it (as the plastic rod is fresh, not worn from slipping out) but I agree, terrible design and will most likely happen again. When the company that did the work called TT to review, they were told they should add extra piping on the primary loop as a bypass as indicated in previous post.