heat to AC changeover?

[micky]

What could this guy be talking about? It takes weeks to swtich from heat to AC? On a building built in 1970?

"Why did I want a portable air conditioner? I live in a condominium apartment that was constructed in 1970. The hvac system is one that can supply either air conditioning or heat but is not easily converted. This is a central unit that serves all 300+ units. The heat is turned off around mid-April and over a period of weeks is converted to provide air conditioning on May 15th. I live in the Washington DC area and we have some very warm days between these dates. "

His last sentence is true some years, although inside my house it doesn't get warm that quickly.

[J Burns]

I was on a ship like that. If we went from the Labrador Current to the Gulf Stream, we might swelter for a couple of days.

Each compartment had a unit with a coil and a fan. For heating, the circulating water came from the boiler. For cooling, it came from a chiller. If they didn't wait for the water to cool, they'd rupture disks.

In addition, I think HVAC guys had to make a change for each compartment unit. The more units you have, the longer it takes.

[trader_4]

Sounds like crappola to me. More likely it's the policy of the condo. And being a condo, the owners could change either the policy or the equipment. If this was a real problem with weeks required to change something over, it would be a disaster for similar buildings, eg office buildings, commercial buildings. I don't ever recall it being a problem. And if it took weeks, what would the cost be? Good grief.

[J Burns]

George Washington University has an HVAC staff of 14, including licensed engineers. It can take 36 hours to change one building, but it's mostly waiting for the water to cool. Working around the clock, they need at least 2 days to do the 130 buildings. A hot-blooded user might wait weeks because they can't start until most people won't mind losing their heat.

[trader_4]

Since you say it takes 36 hours to change over one building and most of that time is waiting for the water to cool, I guess you agree that it's crappola that it actually takes a month to switch over a condo building.

[Ed Pawlowski]

I'd agree with the policy being the factor. Even it is is 106 degrees, we don't turn on the AC before June 1.

[J Burns]

I don't know if changing a condo could be as much work as changing a campus building. If it were, GWU's crack staff of 14 might do it in 5 days. A smaller staff might take a month.

I imagine another possibility. Maybe the condo depends on a contractor, and it has to be scheduled months ahead. To reduce complaints of being cold, maybe it's not scheduled to start until May 10. If it gets hot in April, the board says, "We're working on it."

A four-pipe system makes both heating and cooling water available to each unit. A developer can save money by using only two pipes, although it entails annual discomfort and labor costs.

[Ralph Mowery]

The old save a dollar system. Use one set of pipes and coils and switch either hot or cold water instead of using 2 systems so you can have either cool or heat whenever you want. So everyone gets hot or cold at the same time even if you want it the other way.

[micky]

Most? swimming pools in Maryland have that policy too. I understood it when I lived further North and it was never hot in May, but here it's hot in May sometimes and in September for sure. I know it has to do with school kids, but when I went to school The weekday before Memorial Day was our last day, and the day after Labor Day our first. They don't do that here either.

[Mark Lloyd]

[snip]

For my mother's parents, it was 105 when they lived near Phoenix Arizona. It was very dry there.

Here (east Texas) 80 degrees can be too hot.

[Ralph Mowery]

I would hate to live like that. In my house with a heatpump or the house I used to live in with air and a gas furnace, I could go from heat to cool in the length of time it takes to walk to the thermostat. During the spring and fall, it is often heat at night and cool during the day.