Single wide heating question

[jubangy]

Ok I read all these questions asking why there is hardly any heat on one side of doublewide, and hardly none on the other.

My question is about the same for a single wide.

After reading through the old forums and getting some ideas too try I found out most of my problem, there was a wad of insulation one of the previous owners stuffed in the trunk right before the vent in our kitchen, took it out now there is heat up there. The problem I am having now is my dining room, it is the only room where the vents are not in the trunk, they appear to have ducting running to them as they are along the outside of the room and there are 4 of them. My question is, can I eliminate 2 of them and put the remaining 2 in the trunk like the rest?
Or, is it possible to build some kind of deflector to put in the trunk somewhere to push more heat to the front and alittle less to the back of my house?

My bedrooms, and bathroom are pretty toasty, while the front half even now that there is heat flowing to and out of the vents, there still is nowhere near as much as the back half. But if I put the vents in the dining room in the trunk line will that kill the front half even more?
I think the deflector would be a good place to start if possible.
Any ideas, thoughts?

Thanks

[Robert]

Having 4 in one room would lead me toward it being something other than just supply registers.


MH's have different styles depending on age, so before you change anything, be sure you know what it is actually for.


Changing the airflow needs to stay in line with static pressure specs and keep heat removed from furnace area.


Just do your homework and move slowly when trying to modify MH ducts.



Take care and best wishes,
Robert

[jubangy]

Well this is the only room in the house that does not have the vents sitting in the trunk. also, this room has 2 additions to it that have been added over the years but it don't look like they goofed with the duct work setup as the belly insulation is still intact underneath. But on the other side of this room another room was added, and they cut into the vents on this side and added a register for the new room. I have since dug in and made sure that nothing was left open or disconnected where these vents were added but again things were pretty tight.

I still think it has to do with the main vents in the dining room being ran with ducting from the main trunk instead of the vents sitting in the trunk as the rooms past this one still have decent air flow/heat and the vents for the front rooms also sit in the main trunk.

I am going to try and take some pictures of it sometime this weekend, I have to replace the rechargeable batteries for my camera, but I want to get you some pictures as I am also a little boggled with the cold air return setup. There is a somewhat big grate in the kitchen that looks like a cold air return and there is cold air coming through it, I don't know if it's hooked up or not though. But there is also the filter in the furnace door, a little hold cut in the floor right in front of the furnace and the doors in the house have been chopped at the bottom so there is like 3/4" or so gap at the bottom. I have been reading these forums about it but still can't quite get a clear picture of what is what when it comes to the cold air return. I am pretty well versed in regular housing heating and ac, but m/h's are quite new to me, so far it hasn't been too difficult lol.
Anyway, thanks Robert for your help and this site, so far 1 night of reading and I was able to fix a air flow problem that plagued me for close to 3 years as I am not really able to crawl underneath, and after reading on here I found one of them "why the hell didn't I think of that" kind of answers suggesting the flashlight and mirror tip.

Thanks again.

[jubangy]

Ok, I had my uncle take a look at the duct setup in my dining room as he is in the hvac feild, he said that the registers were "branch lines" or something like that as they ran some what looks like aluminum duct work to the registers, and it is hooked to the main trunk. However, he said that they should of put dampers in it to help control the air flow through to these registers.

I forgot to have him look at the register looking thing under my cupboard in the kitchen though. Were there regular cold air returns in these mobile homes in 72' or did they make them how they are now with the gaps under the doors and what not?
Thanks

[Manitoba Bill]

I defer to Robert when It comes to these things but these sites have some links to articles about air flow. My 74 single-wide has 2 ducts going to a front addition but no cold air returns.

http://oikos.com/esb/44/forcedair.html

http://oikos.com/esb/index.html#44

[Robert]

MH's have two types cold air returns. Either the return is through front louvered panel of funace and the home itself is the ducting, which is why the gaps are under the doors.

OR


If old enough, the return is through floor registers into the belly and then up into furnace from below.

When you add branches, you should add dampers to divert airflow.


Also, might want to consider that they may have added additions without increasing a/c and/or furnace size and thus also did not increase motor size.


Units there were designed for the home as is, when additions are added, so must the units increase.


MH ducting is a pain in and of itself, when added to, you can create a monster that can devour you in the end if not very careful.


Main things are the ESP of ducts and temps inside heat chamber.


Take care and best wishes,
Robert

[Manitoba Bill]

Robert; Is there any way of calculating air flow properties for furnace/ducts etc. Or is this an HVAC secret formula.

Reason I ask is, as many here, I inherited an old mobile that had an oil-fired furnace replaced with electric. The fan also had an adjustable drive pulley and I had no idea what was the proper size to use/replace it with.

It is a balance between blowing enough air matched to the ducting or overheating the furnace.

[Robert]

Manual J for sizing units, Manual D for sizing ducts.

The units should have airflow data listed on them.

You can take esp (external static pressure ) readings to keep in line.


1 ton = 400 cfm is a norm.


MH's are an art unto themselves though and cannot be totally balanaced to the norm, so it can be trial and error sometimes at best.


Alot of equipment to take different readings will give an idea where it is at and adjust to close as possible of data specs for unit and Manual D for ducts.


Thanks,
Robert

[jubangy]

MH's have two types cold air returns. Either the return is through front louvered panel of furnace and the home itself is the ducting, which is why the gaps are under the doors.

OR


If old enough, the return is through floor registers into the belly and then up into furnace from below.

When you add branches, you should add dampers to divert airflow.


Also, might want to consider that they may have added additions without increasing a/c and/or furnace size and thus also did not increase motor size.


Units there were designed for the home as is, when additions are added, so must the units increase.


MH ducting is a pain in and of itself, when added to, you can create a monster that can devour you in the end if not very careful.


Main things are the ESP of ducts and temps inside heat chamber.


Take care and best wishes,
Robert

Ok this is what has me boggled, there is louvers in the furnace door, as well as a filter in the furnace door. The doors in the house are cut at the bottom so there is probably 1/2 to 3/4" gaps at the bottom of the doors. But, in the kitchen under a cabinet, there is a cold air return at least that what it looks like the grate on it is pretty big, and the last time I was under there there was a fair amount of cold air coming out of it and the first time I looked under there when cleaning the place when we got it, there was enough mouse poison under there to kill a small fleet of mice.

There are 3 small additions that were added (before I bought it) mainly just to extend the width of the rooms they were added to. There also is like a sun room that was added, which is roughly half the 20-27' long, by about 10-15' wide, I am guessing as I have never measured it but it is pretty decent living room. They put a nice size gas space heater in this room, but also have two of the ducts form the dining room cut so they blow out to this room as well. Thing is there is enough air coming out to this addition the way it is, although not great but you do feel a difference. The ducts that feed this, hardly blow at all though in the dining room. There are no dampers on anything other then the louvers on the registers themselves. However, there is pretty decent airflow to the very front of the house which it has to blow through the living room to get to the front, which is what is baffling me, but I am pretty sure it is like you said dampers are needed to divert air into the branch ducts. I still wonder however if it would start a big headache or not by removing the branch ducts and just putting the vents in the trunk line like the rest of the house, as that would eliminate the nightmare of having to go underneath and rip apart the underbelly insulation. The furnace itself is going to get replaced come summer, as I know from experience how dangerous old furnaces can be when heat exchangers crack and go unnoticed/checked. That and I want to put a new furnace in and add ac at the same time. This place is a work in progress, as I did the roof and windows this past summer, and summer of 08 it will be the siding/insulation. and furnace/ac.

As always thanks for your help.

[Robert]

Hi,

Do you have a/c or just heat ?


The grate under kitchen cabinet, does it open into belly area and then exit out of belly (another opening) or does it just open into belly and stop there ?

You say you can feel cold air from there, I take this to mean the belly is open and you feel cold air coming from the grate above ?


Thanks,
Robert

[jubangy]

I just have heat. The grate under the kitchen cabinet, I have no idea where it leads to yer as I haven't been under that end yet, but I can tell you there is quite a bit of cold air coming out of it.

Tomorrow I finally have a day off so I am going to look into it further.

Thanks.

[Robert]

Here's what happens a lot. A system is in, a new system is added and old is left there for others to be unaware of.


If your furnace door panel has louvers and filter, then that IS return air and home is ducting and gaps are for flow under doors when shut.


The things you want to do may or may not work.

You will either in the end be very happy or very sad.



The grate could be where they started to do something and didn't, or from old system.


Main thing is DO NOT ever close off something like that until it is known for sure what it was for.


Mobile homes get modified alot, so go slow.



Thanks,
Robert

[jubangy]

Ok. Thanks Robert.

[Robert]

Hi,

You are very welcome.



Take care and best wishes,
Robert