Modine in Garage -- pipe not getting hot enough to turn on

TraderManSam

: 4 yr old 33K BTU modine in garage. Can't get oil fired boiler pipe hot enough at end of 75' run (that shares mud room heat loop & separate t stat). Pipe gets hot, but only to 120 degrees (using infrared meter to get outside of copper pipe reading) at modine. Aquastat set for 160 degrees . . . goes on when I turn down screw setting to around 120, but blows cool air at that temp. Anti-freeze in system. All other rooms in house are perfectly comfortable. Changed Hi and low setting on boiler Hydrostat from 156 and 180 upward to 180 and 206, but have experienced no change. What's up here? How do I get my modine to work?? (ambient temp in Garage stays about 35 to 40+ degrees as has 2 sides next to inside of house).

Jamie Hall

Not getting enough flow in that pipe -- what controls the flow? Is it in series with the mud room? Or parallel -- and if so, how are the flows between the two balanced?

Solid_Fuel_Man

Is the.whole system glycol? Or is there a heat exchanger of.some type and a circulator for each side of the subsystem?

FWIW, I have a similar sized Modine brand heater in my garage as well. Serves as a heat dump for my wood gasification boiler, turns on if boiler reaches 195, which I try to avoid. Even at 195 water temp and plenty of flow the air is very lackluster. You need to get your Temps very high with those fin-tube type heaters if you want any heat out of them. They work well on steam, but there are better options for water.

Bob Bona_4

Is the modine on a dedicated loop off the boiler with it's own circulator?

TraderManSam

Not getting enough flow in that pipe -- what controls the flow? Is it in series with the mud room? Or parallel -- and if so, how are the flows between the two balanced?
Jamie

JAMIE -- LOOKS TO ME LIKE MUD & GARAGE ARE IN SERIES. SINGLE CIRCULATOR FOR ALL 6 ZONES.

TraderManSam

Not getting enough flow in that pipe -- what controls the flow? Is it in series with the mud room? Or parallel -- and if so, how are the flows between the two balanced?
Jamie

JAMIE -- LOOKS TO ME LIKE MUD & GARAGE ARE IN SERIES. SINGLE CIRCULATOR FOR ALL 6 ZONES.

SOLID FUEL MAN ASKS:
Is the.whole system glycol? Or is there a heat exchanger of.some type and a circulator for each side of the subsystem?

FWIW, I have a similar sized Modine brand heater in my garage as well. Serves as a heat dump for my wood gasification boiler, turns on if boiler reaches 195, which I try to avoid. Even at 195 water temp and plenty of flow the air is very lackluster. You need to get your Temps very high with those fin-tube type heaters if you want any heat out of them. They work well on steam, but there are better options for water.

SOLID FUEL MAN --- ENTIRELY GLYCOL'D THROUGHOUT SYSTEM. NO EXCHANGER. THE THINGS WORKED FINE FOR 3 WINTERS; THIS YEAR -- WON'T TURN ON...ALMOST LIKE THE GLYCOL TURNED TO JELLY AND JUST WON'T FLOW...I DUNNO. WHAT WOULD YOU DO IF YOU WERE ME? I CHECKED TACO HEAD AND AS I SAID, THE PIPE GETS HOT, JUST NOT HOT ENOUGH APPARENTLY. ??? NOW WHAT ???

Bob Bona Asks:
the modine on a dedicated loop off the boiler with it's own circulator?

BOB -- NO DEDICATED LOOP; SHARED WITH MUDROOM, AND ONLY A SINGLE CIRCULATOR FOR ALL 6 ZONES ON THE BOILER; ALL OTHER ZONES (PLUS HOT WATER) WORK FINE AND GET TO TEMP WITHOUT DIFFICULTY. MODINE DOES NOT TURN ON (ANYMORE, IT USED TO) WITH AQUASTAT SET AT 160 DEGREES.

TraderManSam

DOES ANYONE THINK IT'S WORTH SWAPPING OUT THE T-STAT FOR AN OLD ANALOG CONTROL? I MEAN, THE THING CALLS FOR HEAT FROM THE BOILER NOW, BUT IT TAKES AN HOUR OR SO TO GET THE PIPES AT THE MODINE TO SHOW 120 DEGREES USING MY INFRARED READER . . . COULD PIPES BE CLOGGED?

Jamie Hall

It sounds to me as though you just aren't getting to flow to that Modine. If it is in series with the mudroom, can you measure the temperature going into the mudroom radiation and going out, and then going on into the Modine?

TraderManSam

JAMIE SAYS:
It sounds to me as though you just aren't getting to flow to that Modine. If it is in series with the mudroom, can you measure the temperature going into the mudroom radiation and going out, and then going on into the Modine?

JAMIE -- THE MODINE IS IN THE LOOP FIRST, THEN THE T-STATICALLY-CONTROLLED BLOWER FAN (LIKE A KICK-HEATER AT THE FLOOR) IN THE MUD ROOM, AND THAT WORKS FINE, AND AS NOTED IS *AFTER* THE MODINE IN THE SERIES LOOP. SO THIS IS A REAL MYSTERY. IT'S JUST NOT GETTING HOT ENOUGH, SINCE I *CAN* GET MODINE TO TURN ON BY TURNING DOWN THE AQUASTAT VIA A SCREWDRIVER TO ABOUT 120 DEGREES --- BUT THAT IS TOO COOL AND JUST BLOWS COOL AIR WITH NO BTU'S IN IT. THIS IS A REAL MYSTERY TO ME! THINK I SHOULD SWAP THE ROOM T-STAT ON THE MODINE?? COULD THAT BE IT? COULD IT BE THE TACO VALVE (NOT THE HEAD CONTROL), THE VALVE?? COULD THERE BE A DEAD MOUSE STUCK IN THE PIPE?? I FEEL LIKE I'M IN THE TWILIGHT ZONE ON THIS ONE!

TraderManSam

ONE OTHER THING I CAN TELL YOU IS THE MUD ROOM DOES HAVE IT'S OWN T-STAT, SET AT 65 DEGREES, AND I AM WONDERING WHY THERE WOULD BE A 2ND T-STAT ON THE SAME LOOP, AND IF THAT WOULD HAVE ANY EFFECT ON THIS SITUATION??

TraderManSam

ONE OTHER THING I CAN TELL YOU IS THE MUD ROOM, WHILE IT IS ON THE SAME LOOP AS GARAGE, DOES HAVE ITS OWN (I.E. A 2ND) T-STAT CONTROLLER THE TEMP IN THAT INDOOR ROOM, RIGHT NEXT TO THE GARAGE WITH MODINE THAT HAS IT'S OWN T-STAT .... (AMBIENT TEMP IN GARAGE HOVERS AROUND 39 DEGREES DAY AND NIGHT RIGHT NOW IN WINTER. IS IT OK FOR SAME LOOP TO HAVE TWO T-STATS??

TraderManSam

HOW ABOUT IF I SHUT OFF ALL CONTROLS AT THE BOILER ON THE OTHER 5 LOOPS, TURN DOWN THEIR T-STATS (TO OFF) AND THEN TURN THE BOILER HYDROSTAT ALL THE WAY UP TO 220 DEGREES FOR THE *LOW* SETTING??? THAT SHOULD BE THE ULTIMATE TEST TO GET THOSE PIPES RED HOT -- IF THAT DOESN'T WORK, NOTHING WILL ---- CORRECT???

Paul48

Have you bled the loop?

TraderManSam

PAUL 48 asks:
Have you bled the loop

PAUL -- YES, THAT WAS THE FIRST THING I TRIED AND MADE NO DIFFERENCE. I CHANGED TACO HEADS (TWICE) AND NO LUCK, THERE, EITHER. MY GUESS IS THIS IS THE GREATEST STUMPER OF ALL TIME. THERE IS NO LOGICAL REASON FOR THIS.

Paul48

How did you bleed it? Just opening a bleeder at an emitter will not work.

Jamie Hall

Let's go back to square one. The Modine is first. Therefore it's not a problem of low temperature from the mudroom. Therefore, there can be only two possibilities: wildly insufficient flow (that air bound condition) or low input temperature.

But let's look at one other thing: you have two thermostats on that loop? What does each thermostat do? Or not do? Have you checked to make sure that when the Modine thermostat is calling that you have loop flow? It is OK to have two thermostats -- but they both have to control the same valve, and both have to work.

Bob Bona_4

Really sounds like a flow issue. Wonder what pump you've got.

Paul48

He has parallel flow. It worked before. He's replaced the head of the zone valve twice.

Bob Bona_4

Not so sure it ever really "worked", Paul. But thanks.

Paul48

True, but at least it would turn on with 160* water. I put the conditions up there, as much for myself, as anybody else. I can't tell you how many times I've burned myself, by going away from troubleshooting rule #1....easiest to hardest.

TraderManSam

FIRST, I HAVE NO CLUE HOW TO PROPERLY BLEED THE SYSTEM. I OPENED THE DRAIN VALVE, REMOVED ABOUT 1/2 GALLON AND THEN ADDED MORE H2O BY BRINGING psi BACK UP TO 20 LBS PER SQ INCH. FOLLOWING THAT I SHUT 5 OF 6 T-STATS IN THE HOUSE, TURNED OFF ALL ZONES AT BOILER WITH FLOW VALVES TO "OFF" EXCEPT FOR THE MUD-ROOM/GARAGE. JUMPED #2 AND #3 SCREWS ON MODINE TACO VALVE HEAD CONTROL, THEN TURNED UP MODINE T-STAT FROM 39 DEGREES TO 54; 2 MINUTES LATER THE BOILER CALLED FOR HEAT. A VERY FEW MINUTES LATER, THE MODINE WORKED AND BLEW HOT AIR. SO THAT SUPPOSEDLY TOLD ME THE TACO HEAD VALVE CONTROL WAS BAD. SO I REOPEN ALL OTHER 5 LOOP VALVES, AND TURN ALL 5 OTHER T-STATS BACK TO NORMAL 68 DEGREE SETTINGS AND I CHANGED TACO HEAD 2X'S SINCE THEN, AND ALSO OPERATED BOTH MANUALLY ,AND YES THE PIPE GETS HOT, BUT NOT ENOUGH TO TURN MODINE BACK ON AT 160. IF I TURN DOWN AQUASTAT SCREW TO 120, IT GOES ON, BUT BLOWS COLD AIR. UNACCEPTABLE. AGAIN, ALL OTHER ZONES COMFORTABLE. AQUASTAT AT MODINE 160 DOES NOT TURN ON MODINE. HYDROSTAT WAS SET AT 156/180 DURING ABOVE-DESCRIBED "CLOSED ZONES" TEST; WITH NEW TACO VALVES, I TRIED SETTING HYDROSTAT UP TO 180/206 AND THAT *STILL* MAKES NO DIFFERENCE. I'M STUMPED. SEEMS EVERYONE ELSE IS, TOO. NO? WHAT WOULD Y O U DO ??

Paul48

Close the other 5 loop valves slightly. It's possibly a balance issue. Simply, the water takes the path of least resistance.

Paul48

Can you post a picture of the piping? There's something bothering me about your description of the system. A picture would be worth a thousand words.

TraderManSam

WILL GO GET PHOTO(S) NOW. GIMME A FEW MINUTES. THX!

TraderManSam

Here are three photos of the boiler config. Loop zones. Loop returns. And Boiler itself, with SINGLE circulator. (plus one on lower right of boiler pix for hot water, i think??)

Paul48

Supply valve is closed to the zone on the left in your first picture. It appears to be "mostly" closed.

TraderManSam

It is entirely closed. It's a spare zone. It's stubbed-off if you look really closely at the top. It's the one with the blue corrosion. The first zone on the right is the MUD ROOM/GARAGE supply in question. Please tell me what to "DO" . What o you think about slightly closing other loops to "balance" system? How about BLEEDING IT of ALL GLYCOL and just going with H2O? Maybe removing the entire boiler and just starting over??

Paul48

Did you say that the zone will work by itself? With all the other zones shut off? By work, I mean completely......t-stat calls, zone valve opens, boiler fires, zone gets hot.

JUGHNE

Does anyone here know if that boiler has a built in boiler bypass for boiler CI protection?

TraderManSam

No. Even with all zones shut down at the t-stat, I still can't seem to get t-stat to call for heat at Modine; tested and replaced batteries, nothing. Can't open TACO valve manually to call for the flow, either. Will be trying to junper the #2 and #3 screw on TACO valve next --- still fooling with it as I write this. HELLLLLLLLLLLLLLLLP!!

Paul48

Check across terminals 1 and 2 with the t-stat calling. You should get 24volts.

TraderManSam

Paul, What does "Check across terminals 1 and 2" mean? You assume I know what I'm doing... As for my re-test with swapped t-stat, NOTHING! Jumping #2 and #3 doesn't get boiler to turn on.... even with swapping out t-stat for MODINE. Turned all zones back on

Paul48

If you jumped 2 and 3 and the boiler won't turn on, you have more going on. It would take someone on-site a while to dope out the wiring. Our chances are not very good. Someone has to dope it out, then start checking with a VOM(volt/ohm meter).

TraderManSam

I was afraid someone was going to say that. All other 5 stats turned back on, boiler fires, all zones heating normally. Modine is not. There are 3 or 4 transformers wired up to the 6 taco valves. Everything's cross-wired, so there can't be any shorts. I think you can see them in the loop photos (or at least the wiring to the Taco heads). We can go to the moon, but not get glycol to flow to my garage . . . Bumma.

Paul48

You need to know your way around a meter.

Jamie Hall

Paul48 said:

You need to know your way around a meter.

And make no assumptions about anything...

Steamhead

Time to call a pro. Where are you located?

TraderManSam

Got a guy coming. Thanks for all the help!

TraderManSam

Problem solved.

Turns out a FAULTY HYDROSTAT was installed by the last "Pro" I hired, and there was always a red light on, warning me there was not enough water inside the boiler....the damn circulator was never turning on. The system was keeping the house warm by gravity feeding the loops; with exception of the MODINE that required lifting the hot water up into the garage. Also the mudroom loop was on a separate loop, but a T'd return . . . so replacing the HYDOSTAT (and also a leaking Hy-VENT) was also necessary. MODINE now works like a charm, just as before. BE ADVISED that the HYDROSTAT was installed NEW only 4 months ago. Thankful that I called in someone who knew what he was doing this time, as the last SET of guys didn't.... I hope I can get back the cost of the HYDOSTAT -- that was one expensive puppy!! Comments welcome on what I should do now.