h_store_properties.rb

module HStoreProperties
  def self.included(base)
    base.extend ClassMethods
  end
  module ClassMethods
    def boolean_h_store_fields_for(property_names)
          property_names.each do |key|
            attr_accessible key
            scope "has_#{key}", lambda { |value| where('properties @> (? => ?)', key, value) }
    
            send :define_method, key do
              properties && properties[key].to_bool
            end
    
            send :define_method, "#{key}?".to_sym do
              send key
            end
    
            send :define_method, "#{key}=" do |value|
              self.properties = (properties || {}).merge(key => value)
            end
          end
        end
      end
    end
end

pump.rb

class Pump < Component
  include HStoreProperties
  
  boolean_h_store_fields_for %w[variable_speed skid_mounted speed_lock flow_lock press_lock]
end

For one thing, you've got commas in your space delimitated array. So all of your methods are going to be something like these

> %w[variable_speed, skid_mounted, speed_lock, flow_lock, press_lock]
#=> ["variable_speed,", "skid_mounted,", "speed_lock,", "flow_lock,", "press_lock"]

Got it fixed now :)