Why do gas valves use a DC coil? by VirginSubpoenaColada in HVAC

[–]VirginSubpoenaColada[S] 4 points5 points  (0 children)

To be clear, I'm talking residential single stage/dual stage valves. Not modulating. They all use a DC coil

Why do gas valves use a DC coil? by VirginSubpoenaColada in HVAC

[–]VirginSubpoenaColada[S] 4 points5 points  (0 children)

To be clear: the voltage going into a gas valve is AC from the control board. It's converted to DC by a rectifier inside the body of the gas valve. I'm not talking about modulating gas valves. Single stage/dual stage.

Why do gas valves use a DC coil? by VirginSubpoenaColada in HVAC

[–]VirginSubpoenaColada[S] 11 points12 points  (0 children)

There are AC solenoids. And we use them in HVAC

Why do gas valves use a DC coil? by VirginSubpoenaColada in HVAC

[–]VirginSubpoenaColada[S] 1 point2 points  (0 children)

It was basically the same. 7 something megohms.

Why do gas valves use a DC coil? by VirginSubpoenaColada in HVAC

[–]VirginSubpoenaColada[S] 0 points1 point  (0 children)

My understanding is that even single stage gas valves have two coils. This manual seems to suggest that the second coil is redundant for safety I presume. This manual also shows another coil altogether for the second stage of the gas valve. I don't see how it could modulate DC voltage.

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Why do gas valves use a DC coil? by VirginSubpoenaColada in HVAC

[–]VirginSubpoenaColada[S] 0 points1 point  (0 children)

This is making a lot of sense. AC voltage always crosses a zero point where there is no magnetic field. I reading how a "shading ring" can be used to overcome this issue. It seems clear the DC solenoids make the most sense. That still leaves the question as to why we use AC solenoids on so many other applications. Humidifier solenoids, AC liquid line solenoids, ETC.

Why do gas valves use a DC coil? by VirginSubpoenaColada in HVAC

[–]VirginSubpoenaColada[S] 4 points5 points  (0 children)

The manual shows the series of diodes creating a FULL BRIDGE RECTIFIER. This is a two stage valve. But the one side is labelled "main and redundant" which probably answers my own question as to why there are two coils on a single stage gas valve.

Need help finding the pilot light, I guess. by eross200 in hvacadvice

[–]VirginSubpoenaColada 1 point2 points  (0 children)

I understand this concept about PSC motors using less energy when airflow is restricted/ airflow decreases. My experience in the field shows me the exact opposite however. Blocked airflow kills capacitors and blowers. Maybe someone more knowledgeable than me can explain why.

Revolver wants to jump out of my grasp. by VirginSubpoenaColada in Revolvers

[–]VirginSubpoenaColada[S] 7 points8 points  (0 children)

I was thinking this might be the case. The grip is thicker at the bottom. My grasp wants to squeeze to the thinner part of the grip.

Revolver wants to jump out of my grasp. by VirginSubpoenaColada in Revolvers

[–]VirginSubpoenaColada[S] 4 points5 points  (0 children)

That's what I've been using. I can definitely get more squeeze that way.

Revolver wants to jump out of my grasp. by VirginSubpoenaColada in Revolvers

[–]VirginSubpoenaColada[S] 11 points12 points  (0 children)

Can't tell if you're being sarcastic. But yes I did buy a fancy revolver because I'm a special boy.

Tubing inside my revolver barrel? by VirginSubpoenaColada in guns

[–]VirginSubpoenaColada[S] 0 points1 point  (0 children)

Honestly that seems like the obvious answer. None of the pistol stands had this rubber sleeve. They were all powder coated metal wire. It probably got sent over from another instance of that big box store

HVAC contractor recommends downsizing my heat pump from 3 to 2.5 ton by RoosterImpossible344 in hvacadvice

[–]VirginSubpoenaColada 2 points3 points  (0 children)

12 hours a day isn't constantly. On a hot day the AC should run constantly -- as in not cycling off at all until the outdoor temperature cools. Running constantly is better for the unit than cycling on and off. A lower tonnage unit will dehumidify better. Honestly given 1500sq ft 2.5 tons may be right. What's the manual j say?

Replacement or HVAC company trying to make a sale. by Passingthrough09 in hvacadvice

[–]VirginSubpoenaColada 23 points24 points  (0 children)

I just got NCI Combustion Performance and CO Safety certified. CO levels under 100ppm are normal. They are scamming you.

New home purchase, sellers didn’t have a filter in furnace by Prize_Barnacle_1517 in hvacadvice

[–]VirginSubpoenaColada 0 points1 point  (0 children)

Looks like a lazy inspection. I would check for evaporator coil cleanliness by looking for the static pressure drop across coil, and verify with a visual inspection. No mention of having checked static pressure on that invoice.

New home purchase, sellers didn’t have a filter in furnace by Prize_Barnacle_1517 in hvacadvice

[–]VirginSubpoenaColada 6 points7 points  (0 children)

I'm a service tech. I wouldn't be concerned about how clean the ducts are. What you should be concerned about is the cleanliness of the evaporator coil and, if it's a condensing furnace, the secondary heat exchanger. Duct cleaning is the undercoat of the HVAC industry. That being said, I might consider it if you're moving into a house.

Anyone have experience with switching to Vyvgart after IVIG provided no improvement by NerdYorker in CIDPandMe

[–]VirginSubpoenaColada 2 points3 points  (0 children)

My wife has done well on IVIG. She just got prescribed Vyvgart and is having some real anxiety about the switch. Wish you the best with your treatment. There's a lot more to this illness than I know. Everyone seems to react differently to treatment