Thread Number: 79184  /  Tag: Vintage Dishwashers
Maytag no heat in main wash
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Post# 1031042   4/27/2019 at 21:41 by chetlaham (United States)        

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Why did older Maytag DWs not run the heater during the main wash? I know there were models without heaters, but those that had them never ran them during the main wash on their lower end models.

Post# 1031046 , Reply# 1   4/27/2019 at 22:05 by combo52 (Beltsville,Md)        

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Good Question, Maytag played all kinds of games trying to have lower operating costs, If you look at cycle charts for MT DWs in the 1980s [ all the same year ] they had at least three different major cycle variations for a normal wash cycle regarding number of water changes, cycle times and heater use and any possible temperature holds.


It was like you were looking at charts for three different brands, better performance was differently a Step-Up feature on MT DWs.


John L.

Post# 1031066 , Reply# 2   4/28/2019 at 07:36 by Tomturbomatic (Beltsville, MD)        

The oldest MT DWs with the figure 8 filter and heating element ran the heater all through the 18 minute wash and had complaints about severe etching of glasses, especially in areas with soft water.

Post# 1031100 , Reply# 3   4/28/2019 at 15:55 by chetlaham (United States)        

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I thought energy was cheap back then?

Its interesting though- not sure why- but I remember many years ago always seeing old Maytag DWs in homes with oil heat. Basically a boiler that was always set 180*, often there was a tempering valve when feeding over to shower fixtures. The area had a Maytag dealer too, so I guess it just worked out in that market niche.

And yahhh I noticed that too, main wash increases on high end models. I think its cruel to do that and helped tarnish the Maytag reputation. More people buy BOL and MOL, especially back in the day when DW were new and high priced so having a short main-wash without heat just forced others to buy from others like Whirlpool who did not go to such great lengths to force TOL.

Post# 1031118 , Reply# 4   4/28/2019 at 18:03 by Tomturbomatic (Beltsville, MD)        

Energy has not been cheap since the early 70s when the energy embargo by the oil-producing nations of the middle east against the nations that supported Israel in the 1973 caused prices to soar. Gas lines were long. Oil heated homes could not be heated to warmer than 65 or 68 during the day and had to be kept cooler at night. Dishwashers would start offering drying without heat. Cheap energy was never cheap. We are still discovering energy's true costs.

Post# 1031119 , Reply# 5   4/28/2019 at 18:32 by chetlaham (United States)        

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I know, but having to keep a water heater to 180* ends up being more energy. I don't grasp what Maytag was thinking.

Post# 1031132 , Reply# 6   4/28/2019 at 19:39 by Tomturbomatic (Beltsville, MD)        

Try not thinking, just whoring after Department of Energy stars.

Post# 1031142 , Reply# 7   4/28/2019 at 20:18 by chetlaham (United States)        

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I know, but having to keep a water heater to 180* ends up being more energy. I don't grasp what Maytag was thinking.

Post# 1031143 , Reply# 8   4/28/2019 at 20:19 by chetlaham (United States)        

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Never mind, double post.

But then why do their TOL models run the heater?

Post# 1031247 , Reply# 9   4/29/2019 at 17:48 by chetlaham (United States)        

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Anyone know what year heat was finally added to the mainwash in the BOLs and MOLs?

Post# 1031486 , Reply# 10   5/1/2019 at 18:14 by potatochips (Nova Scotia)        

I have a service manual from the late late 80s before they stopped reverse rack production and moved to the DWU machines, it shows multiple versions of main wash heating, and named them different features like Sani Wash, Temp Boost, or Power Boost. All had different functions like a thermo hold to 140F, or just a timed section in the wash, or a heat on at all parts of the cycle. For the most part you had to spend the money and buy a machine that had a water heat option.


On my WU902 I jumpered the Power Boost switch as it used to extend the wash to 26 minutes AND do a thermo hold to 140F, which is too long to me as the main wash goes for almost 35+ mins. So by jumpering the switch it still does a thermo hold but doent extend the main wash to 26 minutes.

Post# 1031496 , Reply# 11   5/1/2019 at 19:18 by chetlaham (United States)        

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Can you email the manual?

Post# 1031508 , Reply# 12   5/1/2019 at 20:53 by Tomturbomatic (Beltsville, MD)        

Who would or even could keep a domestic water heater at 180F? Not only is that unsafe, but you would need tempering valves for every faucet. I'm not sure that even a dishwasher fill valve would not be harmed by water this hot. If you have lower temperature water, why not use a modern enzyme detergent and whatever extended time wash cycle your machine might offer.

Post# 1031557 , Reply# 13   5/2/2019 at 10:20 by chetlaham (United States)        

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Homes with oil fired boilers and no separate storage tanks.

Post# 1031564 , Reply# 14   5/2/2019 at 11:07 by combo52 (Beltsville,Md)        
Homes With Oil Fired Hot Water Heat

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That also heated the domestic hot water, ALWAYS had a thermostatic tempering valve to control domestic hot water temps, sometimes boilers have to run at more than 200F to properly heat the house and it is down right deadly to ever let domestic water reach temps over 140F.

John L.

Post# 1031593 , Reply# 15   5/2/2019 at 17:01 by Tomturbomatic (Beltsville, MD)        

Even if the boiler heated the domestic hot water with a coil that used boiler water to heat the domestic hot water so that the two never touched?


Post# 1031599 , Reply# 16   5/2/2019 at 19:10 by kenwashesmonday (Haledon, NJ)        

I grew up in a house that had it's original 1927 Thatcher coal-fired steam boiler which was converted to oil with a pre-WWII Timken rotary oil burner.  We kids learned at a very early age that the hot water at the tap was HOT!


Here's a picture of the same boiler, shown without the oil burner conversion:


  View Full Size
Post# 1031626 , Reply# 17   5/2/2019 at 22:53 by chetlaham (United States)        

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Around here many did not have a tempering valves or only supplying faucets. Thermostat regulated to about 180*. Yes the water was that hot.

@Tomturbomatic: Ideally or with homes built today you would have a separate storage tank where the boiler water is pumped through a coil inside the tank. A thermostat is present which triggers the pump and burner cutting off when the right temp is reached. For what ever reason decades past it was very popular in my area to just take a Weil Mclain and use the boiler for both domestic hot water and hot water basebaord always keeping the jacket at 180* year round.

I have no idea if this is true or not as I am not an HVAC tech or expert in HVAC but was told the reason this was done was because if the boiler is allowed to cool down frequently the seals could start to leak over time.

Post# 1031628 , Reply# 18   5/2/2019 at 22:58 by chetlaham (United States)        

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And oh- yes- the when the boiler is directly feeding the home with hot water I think there was an "isolation" coil separating the domestic hot water from the actual boiler water.

Post# 1031631 , Reply# 19   5/2/2019 at 23:18 by chetlaham (United States)        

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Yes there is a coil!


Post# 1031662 , Reply# 20   5/3/2019 at 07:15 by combo52 (Beltsville,Md)        
Replay # 17

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 " Around here there was no tempering valve for domestic hot water, water was about boiler temperature of 180F "


I have never seen such a system in this part of the country and have been told by plumbers that it would never have legal in the last 70 +years, what part of the country are you talking about and in what time period was this system installed ?



Post# 1031677 , Reply# 21   5/3/2019 at 10:29 by chetlaham (United States)        

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Knowledge of codes varied widely back in the day as well as the enforcement of them.

Good example are 3 wire sub-panels which were never legal in the same structure but you can find countless apartments and condos built here and there up until the 90s with 3 wire feeds as well as 10-2 and 6-2 bare ground to the dryer and stove. (code requires the neutral to be insulated when using NM) Disposal or lighting tapped off the SABC, #14 to dinning room receptacles, GFCIs not installed despite being required at the time for that area, ect, ect.

Most of the homes are from the late 40s-50s. Some have tampering some don't, some have it just for the fixtures.

Post# 1031678 , Reply# 22   5/3/2019 at 11:01 by combo52 (Beltsville,Md)        

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Where Are You Talking About, Up There ?


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