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Re: Mitsubishi heat pump not keeping up
I was finally able to crank all three heads full temp and full fan. It was about 32f outside and about 70 in the house. All units put out air between 110 and 115 measured by a pretty accurate meat thermometer. Does this mean my refrigerant is fine and my issue is just based on sizing?
ksm
Re: Mitsubishi heat pump not keeping up
@Kaos Said: @EdTheHeaterMan That unit is a cold climate unit, this specific one delivers 2.5 tons of heat at 5F. They can be paired with up to 130% capacity indoor heads, but you won't get more than what the outdoor unit is capable out of it.
I tend to disagree with the 2.5 ton (30,000 BTUh) at 5°F statement. It is just the way that Heat Pumps operate. you see the colder the outside temperature is, the less heat there is to take from the air and compress it to make the inside warmer. Now a Heat pump that is rated for 2.5 ton at 45°F outside temperature can not possibly generate 30,000 BTU heating capacity at 5F. It is a physical impossibility. Here is the specification sheet from the MXZ-3C30… it clearly states that the heating capacity at 17° outdoor temperature is less then 2 ton.
When it gets to 5° outside temperature, does some magic low temperature fairy come down from the sky and make it produce more heat? I think not. I still stand by my statement that the 30 is too small for the space and that the 36 may have been a better choice.
If you need to understand more about how heat pumps operate, I will be happy to learn ya some basics… Just send me a PM
Re: Question about gas valve placement on the main inside a house, allowed or not?
Unless there is some local rule against it you can have as many valves as you want.
In my area (MA)they like ball valves on gas and the older plug style valve can't be used on any new work.
If they are existing and are in good shape they can remain like when changing a furnace or a water heater
Re: Question about gas valve placement on the main inside a house, allowed or not?
Not that matters, but if those old gas cocks are similar to the ones in my area (NJ) they are certainly NOT full port. I would guess more like "half port."
Re: Question about gas valve placement on the main inside a house, allowed or not?
most of the plumbing and mechanical codes refer you to NFPA 54 for fuel gas practices and component approval. The local AHJ can add additional requirements as @Mad Dog_2 mentioned.
hot_rod
Re: Question about gas valve placement on the main inside a house, allowed or not?
some gas utilities use a gas cock that can be turned off with a tool, aka Cresent wrench, but cannot be turned back on without a special tool. There is a pin on the backside that needs to depress. I think Michigan requires this type of valve at the meter.
hot_rod
Re: Question about gas valve placement on the main inside a house, allowed or not?
Each valve adds more pressure drop. You don't need an isolation valve on the building to keep the water from running back when you remove the meter like you do on a water service. Gas valves don't really corrode and fail the way water valves do.
mattmia2
Re: Question about gas valve placement on the main inside a house, allowed or not?
A full port valve at the lower arrow would be on the line pressure side and would add little if any restriction to the flow to the meter or your building
I would think the utility should require one there to service their meter. Assuming that all belongs to the gas provider?
hot_rod
Re: Question about gas valve placement on the main inside a house, allowed or not?
i never understood the main gas shutoff requiring a tool to shut off, but there is a gas cock on the line just inside the foundation and another after the regulator.
mattmia2
Re: Question about gas valve placement on the main inside a house, allowed or not?
With the recent Task 87 gas rules, it's a game changer for even touching gas cocks before and around a gas meter. No more just shutting the first gas cock & changing an appliance or gas branch or riser cock. Mad Dog
