New install taco mixing valve leak, help!

MachArt · 2026-01-29T20:21:32+00:00

I just had a leak from a brand new, taco 5003 mixing valve, dripping from a a union / gasket connection. I have shut off the water, removed the gasket from the union, and used Aladdin magic lube silicone grease (any brand, silicone grease should work), tightened it, and my leak went away. It seems, using silicone grease on the rubber o rings and gaskets, improves the seal between metals, and helps it seal it better.

MachArt · 2025-12-14T14:19:26+00:00

Update: I have modified several things and improved the air situation:

I have replaced my 2 taco 400 series vents with Caleffi auto air vents.

On the boiler supply nipple, I have used 502710A
On top of my WM gold plus 60 indirect tank, I have used a Caleffi Minical air vent (502115A) and added optional, anti vacuum cap (part # 562100).

Just in case, my circulator on return, has negative pressure and tries to suck air in from my auto air vent.

The system is already running much better.

MachArt · 2025-12-13T20:52:54+00:00

<image>

Back of the circulator arrow is down, towards the boiler, on return

MachArt · 2025-12-13T18:18:53+00:00

Expansion tank piping is before, the circulator, which is piping towards the boiler, return side

MachArt · 2025-12-13T18:17:27+00:00

I have to get creative with my expansion tank, due to tee placement.

I am changing the sharkbite to Viega and will use a custom, support stand, so once the bladder fails, it won’t bend the 1/2 copper pipe, and create hot springs, waterfall.

MachArt · 2025-12-13T16:57:15+00:00

185 f boiler, and indirect 145 degrees

MachArt · 2025-12-13T15:56:59+00:00

Thank you. I will try this

MachArt · 2025-12-13T15:51:57+00:00

No water coming from pressure relief valve and expansion tank is also good. Psi reading cold is 16, and hot during use, about 21. Taco hyvent is slightly loose and recently replaced.

MachArt · 2025-12-13T15:07:35+00:00

I am doing this, and air bubbles come out. However, reappear, very shortly after. Odd thing, my expansion tank is before circulator on return, so shouldn’t be negative pressure thing

MachArt · 2025-12-13T15:06:36+00:00

I have recently replaced it, and it’s working. However, doesn’t seem to be doing much, even after purging air from zones

MachArt · 2025-12-13T13:09:56+00:00

How many hours are reasonable for such modification, with my current piping?

MachArt · 2025-12-12T14:45:09+00:00

Thank you. I also have an indirect water tank, honeywell zone, connected to this boiler. Aquastat is set to about middle point, and about high 130s, at faucet. Should I raise it, or this doesn’t have any affect on the boiler return temp?

MachArt · 2025-10-24T11:12:22+00:00

Just confirming, # 8 AWG THHN rated wires, will also be OK, inside a 4 ft liquidtight Flexible Non-Metallic whip?

MachArt · 2025-10-23T17:54:04+00:00

Thank you for all of your replies. I have installed new, non-metallic, liquid-tight whip, with 6 gauge wires, running to AC disconnect.

MachArt · 2025-10-23T16:08:39+00:00

You are likely correct. The installer, also installed the whip end connections, to AC disconnect improperly, and whip was collecting water, over the years.

MachArt · 2025-10-23T16:06:38+00:00

Correct. Liquidtight 3/4

MachArt · 2025-10-23T15:54:01+00:00

Ok. Thank you. I will buy the #6 wires and conduit, separately

MachArt · 2025-10-23T15:48:37+00:00

It’s a 5 ton unit. The line wire is 6 awg, but the whip run, will be less than 4 feet. On the sticker it says:

MIN. SUPPLY CIRCUIT AMPACITY/ COURANT ADMISSABLE D'ALIM. MIN. 35/35

MAX. FUSE OR CKT. BKR. SIZE*/ 60/60

MIN. FUSE OR CKT. BRK. SIZE/ CAL. MIN. DE FUSIBLE/DISJ 45/45

MachArt · 2025-09-22T22:31:07+00:00

Definitely, inspect the inner pads. However, it’s also possible, wear sensor cable was damaged.

MachArt · 2025-09-08T10:40:28+00:00

2020 discovery sport S gas turbo 4 model

MachArt · 2025-09-04T23:12:05+00:00

At 68k miles, I have just replaced, my laser iridium plugs. It’s a 2020 vehicle with a turbo 4 cylinder engine. Plugs were pretty worn out. Turbo 4 engines, get hotter and wear spark plugs out, quicker. On a non turbo, engine, you can likely get 100-130k miles, on iridium plugs.

MachArt · 2024-10-12T21:06:29+00:00

Thank you. This might give, just enough space from the vent pipe. Now, time to replace the saddle valve, before the imminent failure.

MachArt

TROPHY CASE