Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Carlin EZ Gas bizarre behavior

BrianStMarie Member Posts: 24
Hi everyone,

I recently had a Carlin EZ Gas conversion burner installed on a WGO boiler. Everything worked fine for a day, and then the system died on me. Installer is not returning calls, texts, or emails. Looking for a little guidance before I decide if this is worth having someone look at it or if I should just give it up and replace the whole system.

Behavior is as follows in standby:
1) I cut power to the system and let it sit for a couple minutes, then turn power back on.
2) Using a multimeter across B1 and B2 in L8148A aquastat, VAC starts at 0 and gradually ticks up over a few minutes, finally holding steady around 60VAC.
3) Watching the burner control, the red LED goes from totally dark and gradually brightens over the same period.

If I trigger a call for heat:
1) Aquastat relay vibrates like crazy and voltage over B1 to B2 drops to zero.
2) If I manually close the relay, voltage B1 to B2 jumps to 120VAC and the burner kicks on and fires as normal.
3) When call for heat is satisfied, the voltage between B1/B2 drops to zero and the burner dies; no post purge, etc.

Does anyone have any ideas on what might be causing this behavior? As I mentioned, it did work for the first day.

Thank you.


  • Jamie Hall
    Jamie Hall Member Posts: 22,916
    Something is seriously wrong... B1-B2 and C1-C2 should both be zero with no call for heat. If you jumper TT, the relay should close and both B1-B2 and C1-C2 should go to 120 VAC. There is nothing in there which could cause a ramping voltage.

    Check all your connections before you get electrocuted...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • BrianStMarie
    BrianStMarie Member Posts: 24
    Yep, I looked at the wiring diagrams for the aquastat and burner. It turns out they reversed the constant line voltage and the limit line voltage to the burner. I have no idea how this ever worked at all. Once I swapped the wiring, it started working normally, although my aquastat relay switch still wouldn't close properly without a little nudge. I stretched the spring slightly and it's working for now.

    After such a ridiculous mistake, I'm pretty worried about the quality of the rest of this install. I may just replace the whole thing in the next couple weeks. Thank you for the help.
    HVACNUT Member Posts: 5,744
    edited August 2018
    Dont throw away the system when you really want to throw away the contractor.
    Like Jamie said, there should never be ramping voltage.
    When TT closes, the K contacts in the relay close for the burner and circ. What's the incoming voltage at L1,L2 in the aquastat? If not 120v, check from neutral to ground. Do the same at B1,B2. And what about the circ? 120v to C1,C2?
    Wiring a constant hot to the primary is only to power the status lights or an LCD display for set up, diagnostics and history depending on the model. If the constant hot was wired to Limit instead of L1 (Hot) on the primary you would know because the burner would never shut off so I dont think the wires were crossed.
    On another note, did the contractor install a gas barometric damper in the run of a tee with a spill switch?
    EBEBRATT-Ed Member Posts: 15,317
    Send us a few pictures so we can give it a look. I'm concerned about the contractor you used. I wouldn't use him again
  • Steamhead
    Steamhead Member Posts: 16,723
    @BrianStMarie , where are you located?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • BrianStMarie
    BrianStMarie Member Posts: 24
    @Steamhead I'm located in Boston.

    The wiring was definitely crossed based on the Carlin manual, with limit voltage going to the red/white and line voltage going to the black; that's the reverse of indicated in the manual. Also when I switched it, everything started to work as you'd expect. Multimeter also now shows 0 across B1/B2 when in standby with no ramping. When thermostat is tripped, voltage is about 118 at B1/B2 and C1/C2, though we have no circulator hooked up. L1/L2 is always about 118. TT is about 26.

    I added some pictures for those interested. We just bought this house and I've discovered plenty of wild things about this system after going through a winter with it. Pressure regulator blocking the damper, 50 psi safety release, Tekmar control that's wired up but doesn't actually control the system, internal pressure swings from 20 psi to 50 psi when in use. Also, the chimney is unlined brick (no tile) and about 40' ft tall.

    My biggest concern about the conversion at this point is that they didn't leave me any combustion test results, so I have no idea how well the system is working, which makes me nervous.

    HVACNUT Member Posts: 5,744
    In addition to what you mentioned, it needs new smoke pipe with a GAS draft regulator mounted on the run of the tee (so if you look into the damper, you can see the chimney base). And it NEEDS a spill switch. You should invest in a stainless chimney liner.
    The pressure fluctuations might be from a bad extrol and PRV. Replace the relief valve with a 30 psi.
    The blast tube insertion depth has been played with indicating incorrect set up, or it was corrected.
    Looks like there's back pressure judging from the scorch marks on the jacket at the burner door.
    The aquastat has a 24v transformer. The primary has a 24v transformer. Butting 2 separate power sources. That's at least part if the low voltage problem. How they both lived, I dont know. Well maybe the aquastat is on its death bed.
    Remove the thermostat wiring between the aquastat and the primary. Remove the thermostat wires at the primary that are coming from the N.O. dry contacts on the Tekmar and connect them to TT on the aquastat.
    Connect the spill switch wires to TT on the primary.
    There should not be any soot. The boiler should have been thoroughly cleaned at the time of the conversion.
    Anyway, you need a qualified tech to correct all necessary issues.
  • rick in Alaska
    rick in Alaska Member Posts: 1,452
    The relief valve is also supposed to be mounted vertically, and the gas valve is on the wrong side of the union, unless there is another valve there I can't see. You might want to check the gauge as they have a habit of not reading right. That boiler is only rated at a maximum of 50 psi, so you really don't want that much pressure there at all. Also, check the air in the expansion tank and see if it matches fill pressure. You need to shut down the water feed valve and drain the pressure off the system to add any air to the tank if needed.
  • GBart
    GBart Member Posts: 746
    It also appears that the flue pipe is too close to the wood wall right from the top of the boiler, this was never inspected.

    all flue pipe 18"
  • GBart
    GBart Member Posts: 746
    blow the picture up and read the service ticket

    issues with the chimney?

    please get good quality CO detectors with a digital readout and install one down near the unit and at least one in the living area
  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    If you are looking for someone to take a look at your system contact me at [email protected] I can refer you to someone in the Boston area.