Wow... It's really getting hot out there... Trouble is, it seems, so is my mobile home!
I've got a 26x72 Fleetwood double-wide and I'm having some trouble keeping it cool. The home itself is 4-bedrooms and 2000 sq. ft.. My inside unit is a Vexar A/C unit with an A Coil made by FB Coils -- outside I have a Nordyne S5QD-042KA 3.5 ton condenser.
During the day, the outside unit never shuts off... Really... We have a programmable thermostat, it's set at 75 during the day. 75 would be nice, but it seems that the best it can do during the day is about 85. I am sitting into the western sun, but with all the doors/windows closed, shades drawn and the ceiling fans on high, one would think this unit could at least drag me into the upper 70's.
I've taken the time to clean the condenser outside -- spraying down the exterior coils, but it really wasn't all that dirty. The water came back out crystal clear. The refrigerant pipes are about normal too, one is extremely cold, the other luke warn.
Right now, the house is 80 degrees and the air coming out of the vents is 59.5. When I got home earlier, the air temp was 85 and I was getting about 62 degrees.
I've heard 18 degrees of cooling is about the best one can expect -- so am I expecting too much of this setup? Just something I'm going to have to live with?
I've already placed a warranty call with the A/C vendor, I was just hoping for some advice from the group.
I have noticed several strange cooling related issues with this home, I'm beginning to wonder if they are related... -- the fact that the vents on the left side of the house are colder than the right and the fact that the empty space below the house is much cooler than the outside air... That seems a little odd to me (i.e. maybe a duct leak???).
Thanks!
It's the time of the season...
Check your crossover duct connecting the two home halves trunklines.
Look for about a 12" flex duct hanging below underbelly and running from one side to other.
Best to have all metal crossover.
Next best is two 90* elbows and flex stretched tight in between.
About 20* is good below outside temp.
Thanks,
Robert
Look for about a 12" flex duct hanging below underbelly and running from one side to other.
Best to have all metal crossover.
Next best is two 90* elbows and flex stretched tight in between.
About 20* is good below outside temp.
Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?
Robert,
Thanks for the information...
I'm actually quite familiar with the duct on this home -- shortly after we moved in, we awoke one morning to find no heat, it was 40 outside and 50 in the house. Turns out, the duct was not correctly installed and had fallen... I had been heating my slab for about 8 hours. Nice...
So, needless to say, I'm a little leary in thinking the duct is a problem, one would only hope that the last time they fixed the duct, it was fixed permantenly... But then again...
And this is actually a piece of flex between both halves.
And 20 degrees below OUTSIDE temp. or RETURN AIR temp?
Thanks for the information...
I'm actually quite familiar with the duct on this home -- shortly after we moved in, we awoke one morning to find no heat, it was 40 outside and 50 in the house. Turns out, the duct was not correctly installed and had fallen... I had been heating my slab for about 8 hours. Nice...
So, needless to say, I'm a little leary in thinking the duct is a problem, one would only hope that the last time they fixed the duct, it was fixed permantenly... But then again...
And this is actually a piece of flex between both halves.
And 20 degrees below OUTSIDE temp. or RETURN AIR temp?
Check it again and we'll go from there.
20* difference between return air and supply air temps.
20* difference between outside ambient air and inside home temps.
Thanks,
Robert
20* difference between return air and supply air temps.
20* difference between outside ambient air and inside home temps.
Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?
Okay Robert... Time to put you on the spot... 
A/C company just left -- I called them and asked them to check the system to see what's up... We've learned several things.
#1. Heat strips are not turning on (they thought they could be causing the heat problem, though I have no HEAT coming from the vents).
#2. The underside tubing is fine, no problem there
The company said, "Well, it's doing the best it can do... You need more return air from a vent further out in the house to pickup the warm air and recirculate it through the system". I only have 1 return, it's on the door to the unit.
Now, I called Fleetwood and told them, and they said "We've never had this problem before, no other complaints... So if its blowing cold air, then there isn't anything we can do".
So, needless to say, I'm not happy.
All of this leads into my questions...
While I was on the phone with the Fleetwood woman, she did mention that the A/C system has to be built to provide the correct BTU's for the home. She advised to get the BTU number off the plate in the closet (63,500) and divide by 12,000. This would provide the size of the unit outside. Well, 63,500 / 12,000 = 5.29. But, I only have a 3.5 ton. She also said to take the sq. footage (2001) and divide by 500. Okay, 2001 / 500 = 4.002, still a 4 ton unit.... But I have a 3.5 ton.
Does this make sense? Is this a battle I can win?
A/C company just left -- I called them and asked them to check the system to see what's up... We've learned several things.
#1. Heat strips are not turning on (they thought they could be causing the heat problem, though I have no HEAT coming from the vents).
#2. The underside tubing is fine, no problem there
The company said, "Well, it's doing the best it can do... You need more return air from a vent further out in the house to pickup the warm air and recirculate it through the system". I only have 1 return, it's on the door to the unit.
Now, I called Fleetwood and told them, and they said "We've never had this problem before, no other complaints... So if its blowing cold air, then there isn't anything we can do".
So, needless to say, I'm not happy.
All of this leads into my questions...
While I was on the phone with the Fleetwood woman, she did mention that the A/C system has to be built to provide the correct BTU's for the home. She advised to get the BTU number off the plate in the closet (63,500) and divide by 12,000. This would provide the size of the unit outside. Well, 63,500 / 12,000 = 5.29. But, I only have a 3.5 ton. She also said to take the sq. footage (2001) and divide by 500. Okay, 2001 / 500 = 4.002, still a 4 ton unit.... But I have a 3.5 ton.
Does this make sense? Is this a battle I can win?
Hi,
63,500 is the heating btu's, not the cooling.
The cooling is listed on the a-coil model number and on/in the condenser model number.
Square footage for sizing is a rule of thumb or as I like to call it "The Rule Of Dumb" .
Get a qualified and reputable hvac contractor, preferrably one with manufactured housing experience.
Have them do an ACCA Manual J Load Calculation on your home for correct and exact size needed.
IF they do not know what that is or hesitate/refuse to do that, keep looking.
Rule of Dumb:
Poorly insulated with cheapo doors and windows and no to limited shade = 1 ton per 400 sq. ft.
Average insulation, shade, etc. = 1 ton per 500 sq. ft.
Well insulated with new top doors and windows and lots of shade = 1 ton per 600 sq. ft.
To REALLY know size needed beyond any doubt= ACCA Manual J Load Calc.
THEN, when correct size is in order:
superheat
subcooling
head pressure
suction pressure
return air and supply air temps
entering and exiting condenser air temps
suction line temp at condenser
wet bulb temp
dry bulb temp
esp of duct
compressor amps
condenser total amps
cfm at return air
Remember, homes will have units sized for the climates it was designed/built for.
If taken elsewhere and sold/delivered/set-up,,,,it could cause it not to be correct.
Hope these help some. They are only way to know IF it is correct size and IF it is doing all it can.
MH hvac will never be equal to that which is expected from conventional homes hvac as it is not designed and installed to meet THAT home in the enviroment where it now sits at time home was placed there.
MH hvac is a generality and has to be expected to only be able to perform to a certain level.
However, when all the above is known and met, in most cases it is tolerable and accepted.
The only alternative is to install new conventional home ductwork and a conventional home unit meeting MH codes.
Do this by utilizing ACCA Manual J (unit) and Manual D (ducts) Load Calcs to ensure correct sizing.
Take care and best wishes,
Robert
63,500 is the heating btu's, not the cooling.
The cooling is listed on the a-coil model number and on/in the condenser model number.
Square footage for sizing is a rule of thumb or as I like to call it "The Rule Of Dumb" .
Get a qualified and reputable hvac contractor, preferrably one with manufactured housing experience.
Have them do an ACCA Manual J Load Calculation on your home for correct and exact size needed.
IF they do not know what that is or hesitate/refuse to do that, keep looking.
Rule of Dumb:
Poorly insulated with cheapo doors and windows and no to limited shade = 1 ton per 400 sq. ft.
Average insulation, shade, etc. = 1 ton per 500 sq. ft.
Well insulated with new top doors and windows and lots of shade = 1 ton per 600 sq. ft.
To REALLY know size needed beyond any doubt= ACCA Manual J Load Calc.
THEN, when correct size is in order:
superheat
subcooling
head pressure
suction pressure
return air and supply air temps
entering and exiting condenser air temps
suction line temp at condenser
wet bulb temp
dry bulb temp
esp of duct
compressor amps
condenser total amps
cfm at return air
Remember, homes will have units sized for the climates it was designed/built for.
If taken elsewhere and sold/delivered/set-up,,,,it could cause it not to be correct.
Hope these help some. They are only way to know IF it is correct size and IF it is doing all it can.
MH hvac will never be equal to that which is expected from conventional homes hvac as it is not designed and installed to meet THAT home in the enviroment where it now sits at time home was placed there.
MH hvac is a generality and has to be expected to only be able to perform to a certain level.
However, when all the above is known and met, in most cases it is tolerable and accepted.
The only alternative is to install new conventional home ductwork and a conventional home unit meeting MH codes.
Do this by utilizing ACCA Manual J (unit) and Manual D (ducts) Load Calcs to ensure correct sizing.
Take care and best wishes,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?
First if you can only cool your home to 80 deg. after the unit has been running all day you do have a problem. The answer "doing all it can do" is a subjective phrase meaning the way it is set up now it might be "doing all it can do" but that doesn't mean the set-up or capacity is correct. Robert's comments are exactly right you have to have a load calculation done this is the only way to find out if your unit is the right size. The factory has mechanical engineers that confiqure the size unit your home needs but it is up to the dealer to install the proper A/C coil,blower and condensing unit and even then as Robert said if it is set-up in a different location then a load calc is your only way of knowing, also if you suspect the wrong size set-up the factory or dealer is not going to take a techs word but it is hard to argue against a load calc. Again to echo Robert have them check the crossover duct size your return air and blower speed.