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I don't know as much as I would like about HVAC systems so I thought I'd describe what my home has and see what people can tell me.
I just bought a 1924 2-story in Los Angeles, it is about 3000 sq feet and the upstairs is maybe a third of that (2 bedrooms + bath). The HVAC systems are much newer than 1924; I don't know the age exactly except for what we've replaced.
My inspector told us there is a forced air gas furnace (in the little California basement), and a heat pump for the upstairs (in a low attic over one of the bedrooms). No one since has used the phrase "heat pump" though, so that's part of what I'm confused about. There's definitely what looks like a big blower unit in the upstairs attic.
There are two compressor-looking units outside the house. One is bigger, for downstairs AC, and was described as "frozen" at inspection time and we had it replaced subsequently. The smaller one I assume is for the upstairs (there's piping running up there that looks like water pipes wrapped in insulation) but I think I've gotten some strange looks when I call it a compressor so it must somehow be different. There are two thermostats, one for upstairs, one for down.
We had everything serviced when we moved in this summer (cost some $$ too because of the new compressor) and the gas company inspected (came back several times because we had to rebuild a vent chimney that was capped, more $$), so filters are reasonably new, etc. There was a problem with the downstairs furnace only coming on in the "On" setting, not the "Auto" setting, but some relays or something were replaced and that passed muster too.
Let's see, what else. There don't appear to be ducts coming from the downstairs to the upstairs -- one of the bedrooms has a square piece of replaced flooring that I'm betting was where an old duct was. There are center ceiling ducts for air from the attic blower and also returns in the walls.
The blowers on both floors clearly work great, they move air so well we had to be told by our inspector there was a problem with the downstairs air compressor!
I must say for the rest of the summer the air conditioning worked great.
Now, the problems.
We're into the start of California winter with outside air temperature in the high 50s to 60s (don't laugh, that's cold to us). Upstairs this evening it appeared we had air blowing that wasn't heated, even with the upstairs thermostat on "Heat / Auto". My wife set it to "Off" so at least we wouldn't have air blowing on us. Downstairs the thermostat was on "Auto" but nothing was blowing. I set the downstairs to "On" and the furnace lit up, the blower came on and warmed up the house. (If I set it back to "Auto" it goes off.)
So, my questions.
1) Does what I have upstairs sound like a heat pump? Is that what they look like, a blower in an attic and a compressor-looking thing outside? (I'm assuming yes.)
2) Is it possible my upstairs is heated by rising air from the downstairs furnace system? (I'm assuming no.)
3) Is it normal not to get heat from the upstairs blower? (I'm assuming no.) How long should we wait to be sure it's heating?
3) Is it odd that I had the problem of my downstairs furnace only coming on at the "On" setting, not "Auto", the relays were replaced to fix that a couple months ago, and now the problem's back? (I'm assuming yes.) Is something burning out relays? What should I make the service guys look at?
4) What's the right name for the compressor-looking unit outside that isn't actually a compressor?
5) How often should we replace filters? I've seen yearly, quarterly, and monthly recommended.
Sorry for the wordy post.
- Don Rice
Los Angeles, CA, USA
I just bought a 1924 2-story in Los Angeles, it is about 3000 sq feet and the upstairs is maybe a third of that (2 bedrooms + bath). The HVAC systems are much newer than 1924; I don't know the age exactly except for what we've replaced.
My inspector told us there is a forced air gas furnace (in the little California basement), and a heat pump for the upstairs (in a low attic over one of the bedrooms). No one since has used the phrase "heat pump" though, so that's part of what I'm confused about. There's definitely what looks like a big blower unit in the upstairs attic.
There are two compressor-looking units outside the house. One is bigger, for downstairs AC, and was described as "frozen" at inspection time and we had it replaced subsequently. The smaller one I assume is for the upstairs (there's piping running up there that looks like water pipes wrapped in insulation) but I think I've gotten some strange looks when I call it a compressor so it must somehow be different. There are two thermostats, one for upstairs, one for down.
We had everything serviced when we moved in this summer (cost some $$ too because of the new compressor) and the gas company inspected (came back several times because we had to rebuild a vent chimney that was capped, more $$), so filters are reasonably new, etc. There was a problem with the downstairs furnace only coming on in the "On" setting, not the "Auto" setting, but some relays or something were replaced and that passed muster too.
Let's see, what else. There don't appear to be ducts coming from the downstairs to the upstairs -- one of the bedrooms has a square piece of replaced flooring that I'm betting was where an old duct was. There are center ceiling ducts for air from the attic blower and also returns in the walls.
The blowers on both floors clearly work great, they move air so well we had to be told by our inspector there was a problem with the downstairs air compressor!
I must say for the rest of the summer the air conditioning worked great.
Now, the problems.
We're into the start of California winter with outside air temperature in the high 50s to 60s (don't laugh, that's cold to us). Upstairs this evening it appeared we had air blowing that wasn't heated, even with the upstairs thermostat on "Heat / Auto". My wife set it to "Off" so at least we wouldn't have air blowing on us. Downstairs the thermostat was on "Auto" but nothing was blowing. I set the downstairs to "On" and the furnace lit up, the blower came on and warmed up the house. (If I set it back to "Auto" it goes off.)
So, my questions.
1) Does what I have upstairs sound like a heat pump? Is that what they look like, a blower in an attic and a compressor-looking thing outside? (I'm assuming yes.)
2) Is it possible my upstairs is heated by rising air from the downstairs furnace system? (I'm assuming no.)
3) Is it normal not to get heat from the upstairs blower? (I'm assuming no.) How long should we wait to be sure it's heating?
3) Is it odd that I had the problem of my downstairs furnace only coming on at the "On" setting, not "Auto", the relays were replaced to fix that a couple months ago, and now the problem's back? (I'm assuming yes.) Is something burning out relays? What should I make the service guys look at?
4) What's the right name for the compressor-looking unit outside that isn't actually a compressor?
5) How often should we replace filters? I've seen yearly, quarterly, and monthly recommended.
Sorry for the wordy post.
- Don Rice
Los Angeles, CA, USA