sidearm or heat plate
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HUSKYMAN
Addicted to ArboristSite
I don't have an OWB but I have been researching them and it is my understanding that the side arm has a lot less heat transfer area and can "run out" of hot water, while a plate exchanger is a virtually limitless provider of hot water. Someone please correct me if I am wrong.
kamhillbilly
ArboristSite Lurker
I am in the same type of project and interested in same answers
A plate exchanger will come in different sizes of plates.there are 10 plate 20 plate up to 100 plate if i remember and yes a a plate exchanger needs no tank and can provide instant hot water .
A sidearm unit is slower and can result in a cold shower and it also requires that you hacve a water tank as it installs on the side.
also a plate exchanger will plug up if there is junk in the boiler water or the fresh water so if you have hard water like I do and your sink taps and shower head clog up you may run into problems later on with a plate .
there are many ways to install both types and remember that without a tempering valve or some sort of temp controll your hot water will be what you set your boiler to.
I have seen a set up where the washing machine set on hot melted the agitator as the boiler was set at 190.
A sidearm unit is slower and can result in a cold shower and it also requires that you hacve a water tank as it installs on the side.
also a plate exchanger will plug up if there is junk in the boiler water or the fresh water so if you have hard water like I do and your sink taps and shower head clog up you may run into problems later on with a plate .
there are many ways to install both types and remember that without a tempering valve or some sort of temp controll your hot water will be what you set your boiler to.
I have seen a set up where the washing machine set on hot melted the agitator as the boiler was set at 190.
Butch(OH)
Addicted to ArboristSite
Well, my 2 cents is neither is what I would call the ideal setup. a combo of both would work OK but would be expensive too. If you are spending little to heat your water now carefully consider all costs before jumping. We used to spend $100 a month the heat water around here (wife is neat freak, LOL) plus 5 for showers.
Plate type pluses
With correct sizing they will heat water as fast as you can run it as long as your boiler is hot.
Installation extras (valves, unions etc) are cheaper.
Plate minuses.
They can clog with debris in the circulating water side
They can cog with lime, rust on the domestic side
During long periods of no usage the heater must run to maintain set temps.
Side arm pluses
They heat the entire tank so burner does not run during long periods of no use.
They don't clog on the boiler side (but still can lime up on the domestic side.)
minuses.
They don't heat water fast, ours would be good enough if there was only 2-3 of us here.
The design of all water heaters puts the cold water to the bottom, right where your water heater's aquastat is located. you have to turn it way down or every time you run some water the burner will light. Then when you use a lot of water the burner wont kick on to help out.
If you make the tube removable without desoldering half your loop you need 5 valves and 4 unions, and a bunch of fittings, all dern expensive when you use copper.
I am going to modify mine for next season but I am not exactly sure how. I have no plans to run mine in the summer so I have a while to figure this out. Its enough to make me wonder if hardy doesn't have it right after all, put a domestic coil in the boiler.
Plate type pluses
With correct sizing they will heat water as fast as you can run it as long as your boiler is hot.
Installation extras (valves, unions etc) are cheaper.
Plate minuses.
They can clog with debris in the circulating water side
They can cog with lime, rust on the domestic side
During long periods of no usage the heater must run to maintain set temps.
Side arm pluses
They heat the entire tank so burner does not run during long periods of no use.
They don't clog on the boiler side (but still can lime up on the domestic side.)
minuses.
They don't heat water fast, ours would be good enough if there was only 2-3 of us here.
The design of all water heaters puts the cold water to the bottom, right where your water heater's aquastat is located. you have to turn it way down or every time you run some water the burner will light. Then when you use a lot of water the burner wont kick on to help out.
If you make the tube removable without desoldering half your loop you need 5 valves and 4 unions, and a bunch of fittings, all dern expensive when you use copper.
I am going to modify mine for next season but I am not exactly sure how. I have no plans to run mine in the summer so I have a while to figure this out. Its enough to make me wonder if hardy doesn't have it right after all, put a domestic coil in the boiler.
bikeralan
ArboristSite Lurker
i have a cozeburn (empire) and use a sidearm heater, am thinking next season of switching to a plate type.
we have had unit in use for 3 yrs now and it just doesn't seem to be constant. it cranks out hot water fine for a while, and then it seems to not to.
My advice would be find someone in your area if possible that has each kind.
good luck
Alan
we have had unit in use for 3 yrs now and it just doesn't seem to be constant. it cranks out hot water fine for a while, and then it seems to not to.
My advice would be find someone in your area if possible that has each kind.
good luck
Alan
stonykill
ArboristSite Guru
I have an owb and heat my hot h20 with a plate exchanger. I never run out of hot water and I actually have to turn the COLD water up in the shower, the longer that I am in there. The water gets hotter the more I run it. We have run 2 dishwasher loads, and taken 3 hot , long showers in a 3 hour period, and never ran out of hot water. The electric hot water heater is off at the breaker box. We just use it as a storage tank.
kamhillbilly
ArboristSite Lurker
Do you pump your hot water through the plate exchanger or just convection(thermo siphon)?Also what size of plate exchanger?
stonykill
ArboristSite Guru
I have a 5000 btu owb. I run the hot water from the boiler thru the heat exchanger for the domestic hot water 1st, then to the heat exchanger for the home heat. My workshop runs off a seperate zone and taco pump. kamhillbilly and kevinjem, check your pm's.
I also use a plate heater(10 plates got it from work (Free) .Have had it for 3 years now and never run out of hot water. They make all types of fittings to hook up the plate heats, mine has a O-ring fitting. When I installed it I placed valves in line so I can take it out and clean it. The hot water runs from stove to plate heater first then to house blower. With my pump running all the time through the plate heater the hot water heater never cuts on. As bassman said you will need to mix your very hot water before stepping into the shower.Go with the plate heater and valve it so you can take it out and clean it.
stonykill
ArboristSite Guru
I feel like Rodney Dangerfield, no respect I tell you. Reread Bassmans post, seems I said something like that, not him...no respect I tell you, no respect...
NOT SURE if you were wondering but with your setup the only time the water gets heated is when it enters the tank and after that it just sits .
It gets hotter cause you are then running out of colder water in the tank.
It will work this way and you prove it does but if the water ran for 2 hours straight you would most likely end up with very hot water the same as the boiler setting.
shayne
windthrown
361 Junkie
Flat plate here...
We have flat plate HXs on both the water hater and hydronic floor loop, in that order. They both have been working great for 2 heating seasons. No clogs, no breaks, no lack of heat. Super hot water, all we want. Faster recovery time than sidearm units. More expensive though.
The hot water HX is low on the loop and works all by itself with the magic of convection. The heat rises in the water loop and heats the whole tank. No need for a pump there. The floor loop has its own circulation Taco pump that comes on when the t-stat in the house calls for heat (70 degrees). The OWB water loop also has a Taco pump that runs all the time.
I recommend a flat plate HX.
We have flat plate HXs on both the water hater and hydronic floor loop, in that order. They both have been working great for 2 heating seasons. No clogs, no breaks, no lack of heat. Super hot water, all we want. Faster recovery time than sidearm units. More expensive though.
The hot water HX is low on the loop and works all by itself with the magic of convection. The heat rises in the water loop and heats the whole tank. No need for a pump there. The floor loop has its own circulation Taco pump that comes on when the t-stat in the house calls for heat (70 degrees). The OWB water loop also has a Taco pump that runs all the time.
I recommend a flat plate HX.
stonykill
ArboristSite Guru
sure, I understand how it works. I think a 2 hour shower would shrivel me up before it got that hot. It could in theory approach 180 degrees, but there is heat loss in the plate exchanger from the cold well water. In order for the water to ever reach the temp on the boiler, the domestic hot water would actually have to run thru the boiler, and it doesn't. they are separate.
Butch(OH)
Addicted to ArboristSite
Too hot?
Cant belive this has progressed this far with out mention of blending valves. You need to install an automatic blending valve to protect yourself and others from being scalded. Mine is a TACO brand and has worked perfectly so far. Blends in cold only when needed, mine is set to start blending at 130.
Cant belive this has progressed this far with out mention of blending valves. You need to install an automatic blending valve to protect yourself and others from being scalded. Mine is a TACO brand and has worked perfectly so far. Blends in cold only when needed, mine is set to start blending at 130.
stonykill
ArboristSite Guru
the blending valve is needed with a sidearm, but not with a plate exchanger as it only dumps in hot water when you open a hot water valve.
It seems to me that one should get the storage as hot as possible whenever heat is available, and always use a tempering (blending) valve. Physics says you should capture all the heat you can, whenever you can. Two tanks would be great, to increase storage capacity. Even when the boiler is too cold to heat the domestic water, it can heat a preheat tank to somewhere between the cold supply temp. and the desired hot water temp.. All BTU are valuable, whether you get them at the low end or the high!
Turning off the lower element in the HWH will allow "some" hot to be stored in the HWH while minimizing the storage losses. Adjusting shower habits to match the availability of hot water from the boiler can make a difference.
Has anyone made a sidearm out of galvanized pipe? It should be cheaper than dirt to do one that way. Tacking some fins to the inner pipe could raise the transfer coefficient considerably. I have seen ads talking about dimpling the inner tube to raise transfer rate. Obviously the outside should be well insulated. Maybe wrapped or put in a box and foamed.
Turning off the lower element in the HWH will allow "some" hot to be stored in the HWH while minimizing the storage losses. Adjusting shower habits to match the availability of hot water from the boiler can make a difference.
Has anyone made a sidearm out of galvanized pipe? It should be cheaper than dirt to do one that way. Tacking some fins to the inner pipe could raise the transfer coefficient considerably. I have seen ads talking about dimpling the inner tube to raise transfer rate. Obviously the outside should be well insulated. Maybe wrapped or put in a box and foamed.
Must be a NY thing! Stonykill as far as rereading look at Bassmans post on 3-19 as He stated the need for a tempering valve. (mixing valve-blending valve) No respect. And as far as the water not getting as hot as the boiler. Mine without the mixing valve coming out of the water heater is 145 deg. coming from boiler to plate heater is 165 deg. Yes the only time you get hot water into the tank is when you turn hot water on some where in the house but most water heaters will hold hot water for some time. You are more the welcome come try a hot shower and and tell me when you run out of hot water.(bring you ducky)
Plate heater are the only way to go.
Plate heater are the only way to go.dont get me wrong as i am sure you have a good feel for how it works .
I just dont want the relatives kids getting scalded in some weird senario and some mom yelling why does it do that and then here comes the law suit.
we have boilers and they are not dummy proof !!
my friend who i asked to fill mine one weekend when i was gone said "there was a log that woulndt fit so can i just leave the door open till it burns down so i can shut it"
at least he called.
I just dont want the relatives kids getting scalded in some weird senario and some mom yelling why does it do that and then here comes the law suit.
we have boilers and they are not dummy proof !!
my friend who i asked to fill mine one weekend when i was gone said "there was a log that woulndt fit so can i just leave the door open till it burns down so i can shut it"
at least he called.
