Is it ok to connect to the primary pumps PVC before the check valve, eliminating the need for 2 check valves?

No, you need a check valve for each pump. This happened to my sump pump installation: Over time, the flapper (acts like the valve) in the check valve deformed a little, detached from its hinge point(s), and ended up in the FRONT part of the body. This meant that when water was being pumped out of the sump, the water forced the flapper into the check valve opening... BLOCKING the flow! The check valve ended up working backwards, basically. With the water unable to flow, after enough time, the sump pump burned itself out. If two pumps are feeding through just one check valve, the same thing could happen to both pumps. Each pump needs its own check valve. It's OK for the discharge lines to merge afterwards. BTW: If you really depend of a reliable sump pump installation, spend the extra $30-$50 bucks and get a couple of industrial-strength check valves (regardless if you have a single or double-pump system). They will be "out of sight and out of mind" parts of your installation; you need to KNOW that they'll last!

What size pvc pipe goes into the single fitting at the top of the unit,and what method are you using to attach it? Thanks

I glued a three-foot section of 1-1/2" PVD pipe to the wye-fitting at the top of the pump assemble. At the top of the three-foot section I used an 1-1/2" Fernco rubber coupler with stainless steel clamps to connect it to the drain line. You're going to love this pump. It's the quietest pump I've ever heard.

Can anyone please recommend a battery to purchase for this unit?

I installed a VMAX 127 deep cell battery. It provides between 36-48 hours of pumping capacity. Cost ~$300. I recommend you don't go cheap on the battery.

ASIN	B07H4S6X9N
Brand	Wayne
Brand Name	Wayne
Color	Black
Colour	Black
Customer Reviews	4.4 out of 5 stars 1,411 Reviews
EU Spare Part Availability Duration	3 Years
Flow Rate	85 Gallons Per Minute
Global Trade Identification Number	00040066218506
Included Components	combination system
Item Dimensions L x W x H	34.3L x 22.9W x 39.4H centimeters
Item Type Name	1/2 HP and 12-Volt Battery Back Up System
Item Weight	19.96 kg
Manufacturer	WAYNE
Material	Cast Iron
Material Type	Cast Iron
Maximum Lifting Height	20 Feet
Model Number	WSS30VN
Power Source	Air Powered
Power source	Air Powered
Product Style	WSS30V combination sump pump system
Product dimensions	34.3L x 22.9W x 39.4H centimeters
Style	WSS30V combination sump pump system
UPC	040066218506
Unit Count	1 Count
Voltage	12 Volts

1/2 HP Sump Pump with Integrated Vertical Float Switch and 12 Volt Battery Back Up Capability, Battery Not Included - Up to 5,100 Gallons Per Hour - Heavy Duty Basement Sump Pump System

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